Dermatopathology

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Milia En Plaque 

Biopsy results revealed a normal epidermis; the dermis showed multiple small cystic structures lined by a stratified squamous epithelium containing eosinophilic keratin surrounded by a mononuclear cell infiltrate and some melanophages (Figure).  

Milia en plaque was first described in 1903 by Balzer and Fouquet.¹ In 1978, Hubler et al² presented 2 cases with an asymptomatic, erythematous, and edematous plaque and white milialike lesions. On histopathology, they showed multiple cystic structures characterized by central laminated keratin and an intense polymorphic inflammatory reaction surrounding the cyst and epidermal appendages. Both patients were treated with topical tretinoin with complete response at 3 months. The authors suggested the term milia en plaque to describe this clinical entity.² 

Milia en plaque is described as an infrequent condition that more often presents on the head, neck, and trunk, as well as the periocular, periauricular, and perinasal areas. It has been reported to occur at any age³ but appears more frequently in middle-aged adults and females. A congenital case also has been reported.⁴ It has been associated with pseudoxanthoma elasticum, lichen planus, trauma, kidney transplant, and cyclosporine use, but it also can present in healthy individuals,³ as in our patient. No clear cause has been identified. 

Pathology is characteristic, with multiple cysts filled with keratin and surrounded by 2 or 3 layers of epithelial cells, associated with a mononuclear, nonlichenoid, mononuclear infiltrate.⁵ Structures similar to follicular infundibular tumors have been described, suggesting a common origin of follicular lesions as milia en plaque.⁶  

Treatment includes surgical excision, cryosurgery, dermabrasion, electrodesiccation, trichloroacetic acid, photodynamic therapy, CO₂ and erbium lasers, topical retinoids, minocycline, and etretinate.⁷ We performed a complete surgical excision in our patient.  

In acneform reactions, erythematous papules and pustules can be found on the cheeks and forehead. Nevus comedonicus appears during childhood and presents with multiple open comedones. Postinflammatory milia is present in chronic inflammatory pathologies such as porphyria cutanea tarda. Histopathologic findings in adnexal tumors show a benign proliferation of any cellular type of a cutaneous annex. 

Milia en plaque is an unusual but benign condition that is distinguished clinically by its characteristic presentation. 

The Diagnosis: Microvenular Hemangioma  

Microvenular hemangioma is an acquired benign vascular neoplasm that was described by Hunt et al¹ in 1991, though Bantel et al² reported a similar entity termed micropapillary angioma in 1989. Microvenular hemangioma typically presents as a solitary, slowly enlarging, red to violaceous, asymptomatic papule, plaque, or nodule measuring 5 to 20 mm in diameter. It usually is located on the trunk, arms, or legs of young adults without any gender predilection. Microvenular hemangioma is rare.³ The etiology has not been elucidated, though a relationship with hormonal factors such as pregnancy or hormonal contraceptives has been described.²  

Histopathologically, microvenular hemangioma has a characteristic morphology. It is comprised of a well-circumscribed collection of thin-walled blood vessels with narrow lumens (quiz image).⁴ The blood vessels tend to infiltrate the superficial and deep dermis and are surrounded by a collagenous or desmoplastic stroma. The endothelial cells are normal in size without atypia, mitotic figures, or pleomorphism. A mild lymphoplasmacytic inflammatory infiltrate sometimes is present. Microvenular hemangioma expresses many vascular markers confirming its endothelial origin, including CD34, CD31, WT1, factor VIII-related antigen, and von Willebrand factor.³ Moreover, WT1 staining suggests the lesion is a vascular proliferative growth, as it usually is negative in vascular malformations due to errors of endothelial development.⁵ In addition, it lacks expression of podoplanin (D2-40), which also supports a vascular as opposed to a lymphatic origin.⁴  

Cutaneous angiosarcoma is a rare and highly aggressive malignant neoplasm of the vascular endothelium with a predilection for the skin and superficial soft tissue. Clinical presentation is variable, as it can arise sporadically, commonly on the scalp and face of elderly patients, in areas of chronic radiation therapy, or in association with chronic lymphedema (Stewart-Treves syndrome).⁶ Sporadic neoplasms appear clinically as purpuric macules, plaques, or nodules and are more common in elderly men than women. They are aggressive tumors that tend to recur and metastasize despite aggressive therapy and therefore carry a poor prognosis.⁷ Histopathologically, well-differentiated tumors are characterized by irregular dissecting vessels lined with crowded inconspicuous endothelial cells (Figure 1). Cutaneous angiosarcoma is poorly circumscribed with marked cytologic atypia, and the vessels can take on a sinusoidal growth pattern.⁸ 

Kaposi sarcoma (KS) is a virally induced lymphoangioproliferative disease, with human herpesvirus 8 as the implicated agent. There are 4 principal clinical variants of KS: epidemic or AIDS-associated KS, endemic or African KS, KS due to iatrogenic immunosuppression, and Mediterranean or classic KS.⁹ Cutaneous lesions vary from pink patches to dark purple plaques or nodules that commonly occur on the lower legs¹⁰; however, the clinical appearance of KS varies depending on the clinical variant and stage. Histopathologically, early lesions of KS exhibit a superficial dermal proliferation of small angulated and jagged vessels that tend to separate into collagen bundles and are surrounded by a lymphoplasmacytic perivascular infiltrate. These native vascular structures often are surrounded by more ectatic neoplastic channels with plump endothelial cells, known as the promontory sign (Figure 2).¹¹ With more advanced lesions, the proliferation of slitlike vessels becomes more cellular and extends deeper into the dermis and subcutis. Although the histopathologic features vary with the stage of the lesion, they do not notably vary between clinical subtypes. 

Targetoid hemosiderotic hemangioma, also known as hobnail hemangioma, is a small, benign, vascular tumor that usually affects the trunk, arms, and legs in young to middle-aged adults without a gender predilection. Clinically, it appears as a small, solitary, red to purple papule or macule that typically is surrounded by a pale thin area and a peripheral ecchymotic ring, creating a targetoid appearance, thus the term targetoid hemosiderotic hemangioma.¹² Histopathologically, there is a prominent dermal vascular proliferation. In the papillary dermis, there are dilated superficial vessels lined with a single layer of endothelial cells characterized by a plump, hobnail-like appearance that protrude into the lumen (Figure 3). In the deeper dermis, the vascular spaces are angulated and slitlike and appear to dissect through collagen bundles. Hemosiderin, thrombi, extravasated erythrocytes, and a lymphocytic infiltrate also are often seen.¹³  

Tufted angioma is a rare benign vascular lesion that usually presents as an acquired lesion in children and young adults, though it may be congenital. It is commonly localized to the skin and subcutaneous tissues. Clinically, the lesions appear as red to purple patches and plaques that typically are located on the neck or trunk. More than 50% of cases present during the first year of life and slowly spread to involve large areas before stabilizing in size.¹⁴ Partial spontaneous regression may occur, but complete regression is rare.¹⁵ Lesions usually are asymptomatic but may be painful during periods of platelet trapping (Kasabach-Merritt phenomenon), which may develop in congenital cases. Tufted angioma is named for its characteristic histopathologic appearance, which consists of multiple discrete lobules or tufts of tightly packed capillaries in a cannonball-like appearance throughout the dermis and subcutis (Figure 4).^14,15  

The Diagnosis: Microvenular Hemangioma  

Microvenular hemangioma is an acquired benign vascular neoplasm that was described by Hunt et al¹ in 1991, though Bantel et al² reported a similar entity termed micropapillary angioma in 1989. Microvenular hemangioma typically presents as a solitary, slowly enlarging, red to violaceous, asymptomatic papule, plaque, or nodule measuring 5 to 20 mm in diameter. It usually is located on the trunk, arms, or legs of young adults without any gender predilection. Microvenular hemangioma is rare.³ The etiology has not been elucidated, though a relationship with hormonal factors such as pregnancy or hormonal contraceptives has been described.²  

Histopathologically, microvenular hemangioma has a characteristic morphology. It is comprised of a well-circumscribed collection of thin-walled blood vessels with narrow lumens (quiz image).⁴ The blood vessels tend to infiltrate the superficial and deep dermis and are surrounded by a collagenous or desmoplastic stroma. The endothelial cells are normal in size without atypia, mitotic figures, or pleomorphism. A mild lymphoplasmacytic inflammatory infiltrate sometimes is present. Microvenular hemangioma expresses many vascular markers confirming its endothelial origin, including CD34, CD31, WT1, factor VIII-related antigen, and von Willebrand factor.³ Moreover, WT1 staining suggests the lesion is a vascular proliferative growth, as it usually is negative in vascular malformations due to errors of endothelial development.⁵ In addition, it lacks expression of podoplanin (D2-40), which also supports a vascular as opposed to a lymphatic origin.⁴  

Cutaneous angiosarcoma is a rare and highly aggressive malignant neoplasm of the vascular endothelium with a predilection for the skin and superficial soft tissue. Clinical presentation is variable, as it can arise sporadically, commonly on the scalp and face of elderly patients, in areas of chronic radiation therapy, or in association with chronic lymphedema (Stewart-Treves syndrome).⁶ Sporadic neoplasms appear clinically as purpuric macules, plaques, or nodules and are more common in elderly men than women. They are aggressive tumors that tend to recur and metastasize despite aggressive therapy and therefore carry a poor prognosis.⁷ Histopathologically, well-differentiated tumors are characterized by irregular dissecting vessels lined with crowded inconspicuous endothelial cells (Figure 1). Cutaneous angiosarcoma is poorly circumscribed with marked cytologic atypia, and the vessels can take on a sinusoidal growth pattern.⁸ 

Kaposi sarcoma (KS) is a virally induced lymphoangioproliferative disease, with human herpesvirus 8 as the implicated agent. There are 4 principal clinical variants of KS: epidemic or AIDS-associated KS, endemic or African KS, KS due to iatrogenic immunosuppression, and Mediterranean or classic KS.⁹ Cutaneous lesions vary from pink patches to dark purple plaques or nodules that commonly occur on the lower legs¹⁰; however, the clinical appearance of KS varies depending on the clinical variant and stage. Histopathologically, early lesions of KS exhibit a superficial dermal proliferation of small angulated and jagged vessels that tend to separate into collagen bundles and are surrounded by a lymphoplasmacytic perivascular infiltrate. These native vascular structures often are surrounded by more ectatic neoplastic channels with plump endothelial cells, known as the promontory sign (Figure 2).¹¹ With more advanced lesions, the proliferation of slitlike vessels becomes more cellular and extends deeper into the dermis and subcutis. Although the histopathologic features vary with the stage of the lesion, they do not notably vary between clinical subtypes. 

Targetoid hemosiderotic hemangioma, also known as hobnail hemangioma, is a small, benign, vascular tumor that usually affects the trunk, arms, and legs in young to middle-aged adults without a gender predilection. Clinically, it appears as a small, solitary, red to purple papule or macule that typically is surrounded by a pale thin area and a peripheral ecchymotic ring, creating a targetoid appearance, thus the term targetoid hemosiderotic hemangioma.¹² Histopathologically, there is a prominent dermal vascular proliferation. In the papillary dermis, there are dilated superficial vessels lined with a single layer of endothelial cells characterized by a plump, hobnail-like appearance that protrude into the lumen (Figure 3). In the deeper dermis, the vascular spaces are angulated and slitlike and appear to dissect through collagen bundles. Hemosiderin, thrombi, extravasated erythrocytes, and a lymphocytic infiltrate also are often seen.¹³  

Tufted angioma is a rare benign vascular lesion that usually presents as an acquired lesion in children and young adults, though it may be congenital. It is commonly localized to the skin and subcutaneous tissues. Clinically, the lesions appear as red to purple patches and plaques that typically are located on the neck or trunk. More than 50% of cases present during the first year of life and slowly spread to involve large areas before stabilizing in size.¹⁴ Partial spontaneous regression may occur, but complete regression is rare.¹⁵ Lesions usually are asymptomatic but may be painful during periods of platelet trapping (Kasabach-Merritt phenomenon), which may develop in congenital cases. Tufted angioma is named for its characteristic histopathologic appearance, which consists of multiple discrete lobules or tufts of tightly packed capillaries in a cannonball-like appearance throughout the dermis and subcutis (Figure 4).^14,15  

The Diagnosis: Microvenular Hemangioma  

Microvenular hemangioma is an acquired benign vascular neoplasm that was described by Hunt et al¹ in 1991, though Bantel et al² reported a similar entity termed micropapillary angioma in 1989. Microvenular hemangioma typically presents as a solitary, slowly enlarging, red to violaceous, asymptomatic papule, plaque, or nodule measuring 5 to 20 mm in diameter. It usually is located on the trunk, arms, or legs of young adults without any gender predilection. Microvenular hemangioma is rare.³ The etiology has not been elucidated, though a relationship with hormonal factors such as pregnancy or hormonal contraceptives has been described.²  

Histopathologically, microvenular hemangioma has a characteristic morphology. It is comprised of a well-circumscribed collection of thin-walled blood vessels with narrow lumens (quiz image).⁴ The blood vessels tend to infiltrate the superficial and deep dermis and are surrounded by a collagenous or desmoplastic stroma. The endothelial cells are normal in size without atypia, mitotic figures, or pleomorphism. A mild lymphoplasmacytic inflammatory infiltrate sometimes is present. Microvenular hemangioma expresses many vascular markers confirming its endothelial origin, including CD34, CD31, WT1, factor VIII-related antigen, and von Willebrand factor.³ Moreover, WT1 staining suggests the lesion is a vascular proliferative growth, as it usually is negative in vascular malformations due to errors of endothelial development.⁵ In addition, it lacks expression of podoplanin (D2-40), which also supports a vascular as opposed to a lymphatic origin.⁴  

Cutaneous angiosarcoma is a rare and highly aggressive malignant neoplasm of the vascular endothelium with a predilection for the skin and superficial soft tissue. Clinical presentation is variable, as it can arise sporadically, commonly on the scalp and face of elderly patients, in areas of chronic radiation therapy, or in association with chronic lymphedema (Stewart-Treves syndrome).⁶ Sporadic neoplasms appear clinically as purpuric macules, plaques, or nodules and are more common in elderly men than women. They are aggressive tumors that tend to recur and metastasize despite aggressive therapy and therefore carry a poor prognosis.⁷ Histopathologically, well-differentiated tumors are characterized by irregular dissecting vessels lined with crowded inconspicuous endothelial cells (Figure 1). Cutaneous angiosarcoma is poorly circumscribed with marked cytologic atypia, and the vessels can take on a sinusoidal growth pattern.⁸ 

Kaposi sarcoma (KS) is a virally induced lymphoangioproliferative disease, with human herpesvirus 8 as the implicated agent. There are 4 principal clinical variants of KS: epidemic or AIDS-associated KS, endemic or African KS, KS due to iatrogenic immunosuppression, and Mediterranean or classic KS.⁹ Cutaneous lesions vary from pink patches to dark purple plaques or nodules that commonly occur on the lower legs¹⁰; however, the clinical appearance of KS varies depending on the clinical variant and stage. Histopathologically, early lesions of KS exhibit a superficial dermal proliferation of small angulated and jagged vessels that tend to separate into collagen bundles and are surrounded by a lymphoplasmacytic perivascular infiltrate. These native vascular structures often are surrounded by more ectatic neoplastic channels with plump endothelial cells, known as the promontory sign (Figure 2).¹¹ With more advanced lesions, the proliferation of slitlike vessels becomes more cellular and extends deeper into the dermis and subcutis. Although the histopathologic features vary with the stage of the lesion, they do not notably vary between clinical subtypes. 

Targetoid hemosiderotic hemangioma, also known as hobnail hemangioma, is a small, benign, vascular tumor that usually affects the trunk, arms, and legs in young to middle-aged adults without a gender predilection. Clinically, it appears as a small, solitary, red to purple papule or macule that typically is surrounded by a pale thin area and a peripheral ecchymotic ring, creating a targetoid appearance, thus the term targetoid hemosiderotic hemangioma.¹² Histopathologically, there is a prominent dermal vascular proliferation. In the papillary dermis, there are dilated superficial vessels lined with a single layer of endothelial cells characterized by a plump, hobnail-like appearance that protrude into the lumen (Figure 3). In the deeper dermis, the vascular spaces are angulated and slitlike and appear to dissect through collagen bundles. Hemosiderin, thrombi, extravasated erythrocytes, and a lymphocytic infiltrate also are often seen.¹³  

Tufted angioma is a rare benign vascular lesion that usually presents as an acquired lesion in children and young adults, though it may be congenital. It is commonly localized to the skin and subcutaneous tissues. Clinically, the lesions appear as red to purple patches and plaques that typically are located on the neck or trunk. More than 50% of cases present during the first year of life and slowly spread to involve large areas before stabilizing in size.¹⁴ Partial spontaneous regression may occur, but complete regression is rare.¹⁵ Lesions usually are asymptomatic but may be painful during periods of platelet trapping (Kasabach-Merritt phenomenon), which may develop in congenital cases. Tufted angioma is named for its characteristic histopathologic appearance, which consists of multiple discrete lobules or tufts of tightly packed capillaries in a cannonball-like appearance throughout the dermis and subcutis (Figure 4).^14,15  

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Cutaneous B-Cell Lymphoma, Follicle Center Subtype 

A 4-mm punch biopsy through the center of the largest lesion on the right posterior shoulder demonstrated a superficial and deep dermal atypical lymphoid infiltrate composed predominantly of small mature lymphocytes with interspersed intermediate-sized cells with irregular to cleaved nuclei, dispersed chromatin, one or more distinct nucleoli, occasional mitoses, and small amounts of cytoplasm (Figure, A). Immunoperoxidase studies showed the infiltrate to be a mixture of CD3+ T cells and CD20+ B cells (Figure, B). The B cells coexpressed B-cell lymphoma (Bcl) 6 protein (Figure, C) but were negative for multiple myeloma 1/interferon regulatory factor 4 and CD10; Bcl2 protein was positive in T cells but inconclusive for staining in B cells. Very few plasma cells were seen with CD138 stain. Fluorescence in situ hybridization studies were negative for IgH and BCL2 gene rearrangement. Molecular diagnostic studies for IgH and κ light chain gene rearrangement were positive for a clonal population. A clonal T-cell receptor γ chain gene rearrangement was not identified. The overall morphologic, immunophenotypic, and molecular findings were consistent with cutaneous involvement by a B-cell lymphoproliferative disorder, favoring primary cutaneous follicle center lymphoma (PCFCL). 

The patient was referred to our cancer center for further workup consisting of a complete blood cell count with differential; comprehensive metabolic panel; lactate dehydrogenase; serum protein electrophoresis; peripheral blood flow cytometry; and computed tomography of the chest, abdomen, and pelvis. The analysis was unremarkable, supporting primary cutaneous disease. Additional studies suggested in the National Comprehensive Cancer Network (NCCN) Guidelines for primary cutaneous B-cell lymphomas include hepatitis B testing if the patient is being considered for immunotherapy and/or chemotherapy due to risk of reactivation, pregnancy testing in women of childbearing age, and human immunodeficiency virus testing.¹ These tests were not performed in our patient because he did not have any risk factors for hepatitis B or human immunodeficiency virus. 

Primary cutaneous B-cell lymphomas originate in the skin without evidence of extracutaneous disease at presentation. They account for approximately 25% of primary cutaneous lymphomas in the United States, with primary cutaneous T-cell lymphoma being most common.² The revised 2017 World Health Organization classification system defines 3 major subtypes of primary cutaneous B-cell lymphoma (Table).^3-9 Primary cutaneous follicle center lymphoma is the most common subtype, accounting for approximately 60% of cases. In Europe, an association with Borrelia burgdorferi has been reported.¹⁰ The extent of skin involvement determines the T portion of TNM staging for PCFCL. It is based on the size and location of affected body regions that are delineated, such as the head and neck, chest, abdomen/genitalia, upper back, lower back/buttocks, each upper arm, each lower arm/hand, each upper leg, and each lower leg/foot. T1 is for solitary skin involvement in which the lesion is 5 cm or less in diameter (T1a) or greater than 5 cm (T1b). T2 is for regional skin involvement limited to 1 or 2 contiguous body regions, whereas T2a has all lesions confined to an area 15 cm or less in diameter, T2b has lesions confined to an area greater than 15 cm up to 30 cm in diameter, and the area for T2c is greater than 30 cm in diameter. Finally, T3 is generalized skin involvement, whereas T3a has multiple lesions in 2 noncontiguous body regions, and T3b has multiple lesions on 3 or more regions.¹¹ At presentation, our patient was considered T2cN0M0, as his lesions were present on only 2 contiguous regions extending beyond 30 cm without any evidence of lymph node involvement or metastasis.  

Treatment of PCFCL is tailored to each case, as there is a paucity of randomized data in this rare entity. It is guided by the number and location of cutaneous lesions, associated skin symptoms, age of the patient, and performance status. Local disease can be treated with intralesional corticosteroids, excision, or close monitoring if the patient is asymptomatic. Low-dose radiation therapy may be used as primary treatment or for local recurrence.¹² Patients with more extensive skin lesions can relapse after clearing; those with refractory disease can be managed with single-agent rituximab.¹³ Our patient underwent low-dose radiation therapy with good response and has not experienced recurrence. 

Lymphocytoma cutis, also known as benign reactive lymphoid hyperplasia, can be idiopathic or can arise after arthropod assault, penetrative skin trauma, drugs, or infections. In granuloma annulare, small dermal papules may present in isolation or coalesce to form annular plaques. It is a benign inflammatory disorder of unknown cause, can have mild pruritus, and usually is self-limited. Pyogenic granuloma is a benign vascular proliferation of unknown etiology. Sarcoidosis is an immune-mediated systemic disorder with granuloma formation that has a predilection for the lungs and the skin. 

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Atypical Fibroxanthoma  

Shave biopsy showed the superficial aspect of a highly cellular tumor composed of pleomorphic spindle cells exhibiting storiform growth and increased mitotic activity (Figure 1). The tumor stained positive for factor XIIIa, CD163, CD68, and smooth muscle actin (mild), and negative for high-molecular-weight cytokeratin (HMW-CK), p63, S-100, and melan-A. Subsequent excision with 0.5-cm margins was performed, and histopathology showed a well-circumscribed tumor contained within the dermis with a histologic scar at the outer margin (Figure 2). There was no lymphovascular or perineural invasion by tumor cells. Re-excision with 0.3-cm margins demonstrated no residual scar or tumor, and external radiation was deferred due to clear surgical margins.  

Atypical fibroxanthoma (AFX) belongs to a group of spindle cell neoplasms that can be diagnostically challenging, as they often lack specific morphologic features on examination or routine histology. These neoplasms--of which the differential includes malignant fibrous histiocytoma, spindle cell squamous cell carcinoma (SCC), desmoplastic melanoma, and leiomyosarcoma--may each appear as a rapidly enlarging solitary plaque or nodule on sun-damaged skin on the head and neck or less commonly on the trunk, arms, or legs. Histologically, the cells of AFX exhibit notable pleomorphism with frequent atypical mitotic figures and nonspecific surrounding dermal changes. Subcutaneous and lymphovascular or perineural invasion of tumor cells can point away from the diagnosis of AFX; however, these features are likely to be missed in small superficial shave biopsies.^1,2 Therefore, immunohistochemistry (IHC) and adequate tumor sampling are essential in the accurate diagnosis of AFX and other spindle cell neoplasms.  

Several IHC markers have been employed in differentiating AFX from other spindle cell neoplasms.^3-8 Positive stains for AFX include factor XIIIa (10%-25%), vimentin (>99%), CD10 (95%-100%), procollagen (87%), CD99 (35%-73%), CD163 (37%-79%), smooth muscle actin (50%), CD68 (>50%), and CD31 (43%). Other stains, such as HMW-CK, S-100, p63, desmin, CD34, and melan-A, typically are negative in AFX but are actively expressed in other pleomorphic spindle cell tumors. The Table summarizes the utility of these various markers in narrowing the differential diagnosis of a spindle cell lesion. Selection of an appropriate panel of IHC markers is critical for accurate diagnosis of AFX and exclusion of more aggressive, poorly differentiated spindle cell neoplasms. Key IHC markers include S-100 (negative in AFX; positive in desmoplastic melanoma), HMW-CK (negative in AFX; positive in spindle cell SCC), and p63 (negative in AFX; positive in spindle cell SCC). Benoit et al⁹ reported a case of a poorly differentiated spindle cell SCC misdiagnosed as AFX based on a limited IHC panel that was negative for pancytokeratin and S-100. Later, a more comprehensive IHC panel including HMW-CK and p63 confirmed spindle cell SCC, but by this time, a delay in therapy had allowed the tumor to metastasize, which ultimately proved fatal to the patient.⁹  

In addition to incomplete IHC evaluation, accurate diagnosis of spindle cell tumors also may be obscured by inadequate tumor sampling. The cells of AFX tumors often are well circumscribed and dermally based, and an excisional biopsy is the preferred biopsy procedure for AFX. A tumor invading into subcutaneous tissue or into lymphovascular or perineural structures suggests a more aggressive, poorly differentiated spindle cell neoplasm.^1,3 For example, the tumor cells of malignant fibrous histiocytoma, which belongs to the undifferentiated pleomorphic sarcoma group, may appear identical to those of AFX on histology, and the 2 tumors display similar IHC profiles.³ Malignant fibrous histiocytoma, however, extends into the subcutaneous space and portends a notably worse prognosis compared to AFX. Malignant fibrous histiocytoma tumors therefore require more aggressive treatment strategies such as external beam radiation therapy, whereas AFX can be safely treated with surgical removal alone. In our patient, complete visualization of tumor margins solidified the diagnosis of AFX and spared our patient from unnecessary radiation therapy. Overall, AFX has a good prognosis and metastasis is rare, particularly when good margin control is achieved.¹⁰ 

Our case highlights the importance of clinicopathologic correlation, including appropriate IHC analysis and adequate tumor sampling in the diagnostic workup of a pleomorphic spindle cell neoplasm. Although these tumors are well studied, their notable degree of clinical and histologic heterogeneity may pose a diagnostic challenge to even experienced dermatologists and require careful consideration of the potential pitfalls in diagnosis.  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶  

The Diagnosis: Wells Syndrome 

Histopathologic examination of the biopsy demonstrated overlying acanthosis, focal spongiosis, and exocytosis. There also was proliferation and thickening of superficial capillaries and papillary fibrosis (Figure, A). There was a mixed interstitial and perivascular inflammatory infiltrate consisting of lymphocytes, histiocytes, plasma cells, and eosinophils (Figure, A and B). Occasional flame figures were identified (Figure, C). 

Wells syndrome, also known as eosinophilic cellulitis, was first described in 1971 by Wells¹ as a recurrent granulomatous dermatitis with eosinophilia. Rarely reported worldwide, this chronic relapsing condition is characterized by a pronounced eosinophilic infiltrate of the dermis resembling urticaria or cellulitis.² The exact etiology has not been elucidated; however, links to certain medications, vaccines, exaggerated arthropod reactions, infections, and malignancies have been documented.³  

Wells syndrome is a diagnosis of exclusion and lacks a predictable dermatologic presentation, thereby mandating focused clinical follow-up as well as correlation with histopathology findings. Although the classic histologic hallmark of Wells syndrome is scattered flame figures, this finding is not specific and can be found in other hypereosinophilic conditions.² Clinical manifestations most often consist of 2 distinct phases: an initial painful burning or pruritic sensation, followed by the development of erythematous and edematous dermal plaques that may heal with slight hyperpigmentation over 4 to 8 weeks. A case series of 19 patients demonstrated variants of Wells syndrome, with an annular granuloma-like appearance found primarily in adults and the signature plaque-type appearance predominating in children.⁴  

Acute urticaria is characterized by pruritic erythematous wheals secondary to a histamine-mediated response brought on by a variety of triggers, typically allergic and self-resolving within 24 hours. When such lesions last longer than 24 hours, biopsy should be performed to exclude urticarial vasculitis, which is characterized by a burning or painful sensation rather than pruritis, in addition to dermal neutrophilia and perivascular infiltrate on histology. Erythema migrans of Lyme disease begins at the site of a tick bite, evolving from a red macule to an expanding targetoid lesion and typically is not pruritic. Infectious cellulitis presents with warm, tender, and poorly defined erythematous patches; can progress rapidly; and is accompanied by systemic symptoms such as fevers, malaise, and lymphadenopathy.  

Best evidence favors the use of moderate- to high-dose corticosteroids as first-line treatment.⁵ The use of tumor necrosis factor blockers, various immunomodulating agents, and combination therapy with levocetirizine and hydroxyzine have demonstrated variable levels of efficacy, albeit often followed by high rates of relapse with drug discontinuation.⁶  

Case Report

A 65-year-old woman presented with stage IVA2 mycosis fungoides (MF)(T4N3M0B2)/Sézary syndrome (SS). A peripheral blood count contained 6000 Sézary cells with cerebriform nuclei, a CD2^+/−CD3⁺CD4⁺CD5^+/−CD7⁺CD8⁻CD26⁻immunophenotype, and a highly abnormal CD4 to CD8 ratio (70:1). Positron emission tomography and computed tomography demonstrated hypermetabolic subcutaneous nodules in the base of the neck and generalized lymphadenopathy. Lymph node biopsy showed involvement by T-cell lymphoma and dominant T-cell receptor γ clonality by polymerase chain reaction.

On initial presentation to the Cutaneous Lymphoma Clinic at the University of Wisconsin-Madison, the patient was erythrodermic. She also was noted to have undulating wavy bands and concentric annular, ringlike, thin, erythematous plaques with trailing scale, giving a wood grain, zebra hide–like appearance involving the buttocks, abdomen, and lower extremities (Figure 1). Lesions were markedly pruritic and were advancing rapidly. A diagnosis of erythema gyratum repens (EGR)–like eruption was made.

Interferon alfa-2b and methotrexate therapy was initiated. Additionally, oral terbinafine (250 mg/d) was initiated for 14 days, resulting in complete resolution of the EGR-like eruption; nevertheless, diffuse erythema remained. Subsequently, within 3 months of treatment, the cutaneous T-cell lymphoma (CTCL) improved with continued interferon alfa-2b and methotrexate. Erythroderma became minimal; the circulating Sézary cell count decreased by 50%. The patient ultimately had multiple relapses in erythroderma and progression of SS. Erythema gyratum repens–like lesions recurred on multiple occasions, with a temporary response to repeat courses of oral terbinafine.

Comment

Defining True EGR vs EGR-like Eruption
Sézary syndrome represents the leukemic stage of CTCL, which is defined by the triad of erythroderma; generalized lymphadenopathy; and neoplastic T cells in the skin, lymph nodes, and peripheral blood. It is well known that CTCL can mimic multiple benign and malignant dermatoses. One rare presentation of CTCL is an EGR-like eruption.

Erythema gyratum repens presents as rapidly advancing, erythematous, concentric bands that can be figurate, gyrate, or annular, with a fine trailing edge of scale (wood grain pattern). The diagnosis is based on the characteristic clinical pattern of EGR and by ruling out other mimicking conditions with biopsy.¹ Patients with the characteristic clinical pattern but with an alternate underlying dermatosis are described as having an EGR-like eruption rather than true EGR.

True EGR is most often but not always associated with underlying malignancy. Biopsy of true EGR eruptions show nonspecific histopathologic features, with perivascular superficial mononuclear dermatitis, occasional mild spongiosis, and focal parakeratosis; specific features of an alternate dermatosis are lacking.² In addition to CTCL, EGR-like eruptions have been described in a number of diseases, including systemic lupus erythematosus, erythema annulare centrifugum, bullous dermatosis, erythrokeratodermia variabilis, urticarial vasculitis, leukocytoclastic vasculitis, and neutrophilic dermatoses.

Prior Reports of EGR-like Eruption in Association With MF
According to a PubMed search of articles indexed for MEDLINE using the terms erythema gyratum repens in mycosis fungoides, mycosis fungoides with tinea, and concentric wood grain erythema, there have been 6 other cases of an EGR-like eruption in association with MF (Table). Poonawalla et al³ first described an EGR-like eruption (utilizing the term tinea pseudoimbricata) in a 55-year-old man with stage IB MF (T2N0M0B0). The patient had a preceding history of tinea pedis and tinea corporis that preceded the diagnosis of MF. At the time of MF diagnosis, the patient presented with extensive concentric, gyrate, wood grain, annular lesions. His MF was resistant to topical mechlorethamine, psoralen plus UVA, and oral bexarotene. The body surface area involvement decreased from 60% to less than 1% after institution of oral and topical antifungal therapy. It was postulated that the widespread dermatophytosis that preceded the development of MF may have been the persistent antigen leading to his disease. Preceding the diagnosis of MF, skin scrapings were floridly positive for dermatophyte hyphae. Fungal cultures from the affected areas of skin grew T rubrum.³

Moore et al⁴ described an EGR-like eruption on the trunk of a 73-year-old man with stage IA MF (T1N0M0B0). Biopsy was consistent with MF, but no fungal organisms were seen. Potassium hydroxide preparation and fungal cultures of the lesions also were negative for organisms. The patient was successfully treated with topical betamethasone.⁴Jouary et al⁵ described an EGR-like eruption in a 77-year-old man with stage III erythrodermic MF (T4N1M0B0). Biopsy showed mycelia on PAS stain. Subsequent culture isolated T rubrum. Terbinafine (250 mg/d) and ketoconazole cream 2% daily were initiated and the patient’s EGR-like rash quickly cleared, while MF progressed to SS.⁵

Cerri et al⁶ later described a case of EGR-like eruption in a 61-year-old man with stage I MF and an EGR-like eruption. Microscopic examination of potassium hydroxide (KOH) preparations and fungal culture of the lesions failed to demonstrate mycotic infection. There was no mention of PAS stain of skin biopsy specimens. In this case, the authors mentioned that EGR-like lesions preceded exacerbation of MF and questioned the prognostic significance of the EGR-like eruption in relation to MF.⁶

Holcomb et al⁷ reported the next case of a 75-year-old man with stage IIB MF (T3N0M0B0) with CD25⁺ and CD30⁺ large cell transformation who presented with an EGR-like eruption. In this case, PAS stain and KOH preparations were repeatedly negative for mycotic infection. Disease progression was not mentioned following the appearance of the EGR-like eruption.⁷

Nagase et al⁸ most recently described a case of a 73-year-old Japanese man with stage IB (T2N0M0B0) CD4⁻CD8⁻ MF and lung cancer who developed a cutaneous eruption mimicking EGR. Microscopy and culture excluded the presence of a mycotic infection. The patient achieved partial remission with photochemotherapy (psoralen plus UVA) combined with topical corticosteroids. No major changes in the patient’s skin lesions were noted following surgical resection of the lung cancer.⁸

Dermatophyte Infection
It is known that conventional tinea corporis can occur in the setting of CTCL. However, EGR-like eruptions in CTCL can be distinguished from standard tinea corporis by the classic morphology of EGR and clinical history of rapid migration of these characteristic lesions.

Tinea imbricata is known to have a clinical appearance that is similar to EGR, but the infection is caused by Tinea concentricum, which is limited to southwest Polynesia, Melanesia, Southeast Asia, India, and Central America. Although T rubrum was the dermatophyte isolated by Poonawalla et al,³ Jouary et al,⁵ and in our case, whether T rubrum infection in the setting of CTCL has any impact on prognosis needs further study.

Our case of an EGR-like eruption presented in a patient with SS and tinea corporis. Biopsy specimens showed CTCL and concomitant dermatophytic infection that was confirmed with PAS stain and identified as T rubrum. Interestingly, our patient’s EGR-like eruption cleared with oral terbinafine therapy, consistent with findings described by Poonawalla et al³ and Jouary et al⁵ in which treatment of the dermatophytic infection led to resolution of the EGR-like eruption, suggesting a causative role.

However, testing for dermatophytes was negative in the other reported cases of EGR-like eruptions in patients with MF, despite screening for the presence of fungal microorganisms using KOH preparation, PAS staining, or fungal culture, or a combination of these methods,^3-8 which raises the question: Do the cases reported without dermatophytic infection represent false-negative test results, or can the distinct clinical appearance of EGR indeed be seen in patients with CTCL who lack superimposed dermatophytosis? In 3 prior reported cases of EGR-like eruptions in MF, the eruption was preceded by immunosuppressive therapy.^5-7

Further investigation is needed to correlate the role of dermatophytic infection in EGR-like eruptions. Our case and the Jouary et al⁵ case reported dermatophyte-positive EGR-like eruptions in MF and SS detected with histopathologic analysis and PAS stain. This low-cost screening method should be considered in future cases. If the test result is dermatophyte positive, a 14-day course of oral terbinafine (250 mg/d) might induce resolution of the EGR-like eruption.

Conclusion

The role of dermatophyte-induced EGR or EGR-like eruptions in other settings also warrants further investigation to shed light on this poorly understood yet striking dermatologic condition. Our patient showed both MF and dermatophytes in skin biopsy results, regardless of whether those sites showed erythroderma or EGR-like features clinically. On 3 occasions, antifungal treatment cleared the EGR-like lesions and associated pruritus but not erythroderma. Therefore, it appears that the mere presence of dermatophytes was necessary but not sufficient to produce the EGR-like lesions observed in our case.

Case Report

A 65-year-old woman presented with stage IVA2 mycosis fungoides (MF)(T4N3M0B2)/Sézary syndrome (SS). A peripheral blood count contained 6000 Sézary cells with cerebriform nuclei, a CD2^+/−CD3⁺CD4⁺CD5^+/−CD7⁺CD8⁻CD26⁻immunophenotype, and a highly abnormal CD4 to CD8 ratio (70:1). Positron emission tomography and computed tomography demonstrated hypermetabolic subcutaneous nodules in the base of the neck and generalized lymphadenopathy. Lymph node biopsy showed involvement by T-cell lymphoma and dominant T-cell receptor γ clonality by polymerase chain reaction.

On initial presentation to the Cutaneous Lymphoma Clinic at the University of Wisconsin-Madison, the patient was erythrodermic. She also was noted to have undulating wavy bands and concentric annular, ringlike, thin, erythematous plaques with trailing scale, giving a wood grain, zebra hide–like appearance involving the buttocks, abdomen, and lower extremities (Figure 1). Lesions were markedly pruritic and were advancing rapidly. A diagnosis of erythema gyratum repens (EGR)–like eruption was made.

Interferon alfa-2b and methotrexate therapy was initiated. Additionally, oral terbinafine (250 mg/d) was initiated for 14 days, resulting in complete resolution of the EGR-like eruption; nevertheless, diffuse erythema remained. Subsequently, within 3 months of treatment, the cutaneous T-cell lymphoma (CTCL) improved with continued interferon alfa-2b and methotrexate. Erythroderma became minimal; the circulating Sézary cell count decreased by 50%. The patient ultimately had multiple relapses in erythroderma and progression of SS. Erythema gyratum repens–like lesions recurred on multiple occasions, with a temporary response to repeat courses of oral terbinafine.

Comment

Defining True EGR vs EGR-like Eruption
Sézary syndrome represents the leukemic stage of CTCL, which is defined by the triad of erythroderma; generalized lymphadenopathy; and neoplastic T cells in the skin, lymph nodes, and peripheral blood. It is well known that CTCL can mimic multiple benign and malignant dermatoses. One rare presentation of CTCL is an EGR-like eruption.

Erythema gyratum repens presents as rapidly advancing, erythematous, concentric bands that can be figurate, gyrate, or annular, with a fine trailing edge of scale (wood grain pattern). The diagnosis is based on the characteristic clinical pattern of EGR and by ruling out other mimicking conditions with biopsy.¹ Patients with the characteristic clinical pattern but with an alternate underlying dermatosis are described as having an EGR-like eruption rather than true EGR.

True EGR is most often but not always associated with underlying malignancy. Biopsy of true EGR eruptions show nonspecific histopathologic features, with perivascular superficial mononuclear dermatitis, occasional mild spongiosis, and focal parakeratosis; specific features of an alternate dermatosis are lacking.² In addition to CTCL, EGR-like eruptions have been described in a number of diseases, including systemic lupus erythematosus, erythema annulare centrifugum, bullous dermatosis, erythrokeratodermia variabilis, urticarial vasculitis, leukocytoclastic vasculitis, and neutrophilic dermatoses.

Prior Reports of EGR-like Eruption in Association With MF
According to a PubMed search of articles indexed for MEDLINE using the terms erythema gyratum repens in mycosis fungoides, mycosis fungoides with tinea, and concentric wood grain erythema, there have been 6 other cases of an EGR-like eruption in association with MF (Table). Poonawalla et al³ first described an EGR-like eruption (utilizing the term tinea pseudoimbricata) in a 55-year-old man with stage IB MF (T2N0M0B0). The patient had a preceding history of tinea pedis and tinea corporis that preceded the diagnosis of MF. At the time of MF diagnosis, the patient presented with extensive concentric, gyrate, wood grain, annular lesions. His MF was resistant to topical mechlorethamine, psoralen plus UVA, and oral bexarotene. The body surface area involvement decreased from 60% to less than 1% after institution of oral and topical antifungal therapy. It was postulated that the widespread dermatophytosis that preceded the development of MF may have been the persistent antigen leading to his disease. Preceding the diagnosis of MF, skin scrapings were floridly positive for dermatophyte hyphae. Fungal cultures from the affected areas of skin grew T rubrum.³

Moore et al⁴ described an EGR-like eruption on the trunk of a 73-year-old man with stage IA MF (T1N0M0B0). Biopsy was consistent with MF, but no fungal organisms were seen. Potassium hydroxide preparation and fungal cultures of the lesions also were negative for organisms. The patient was successfully treated with topical betamethasone.⁴Jouary et al⁵ described an EGR-like eruption in a 77-year-old man with stage III erythrodermic MF (T4N1M0B0). Biopsy showed mycelia on PAS stain. Subsequent culture isolated T rubrum. Terbinafine (250 mg/d) and ketoconazole cream 2% daily were initiated and the patient’s EGR-like rash quickly cleared, while MF progressed to SS.⁵

Cerri et al⁶ later described a case of EGR-like eruption in a 61-year-old man with stage I MF and an EGR-like eruption. Microscopic examination of potassium hydroxide (KOH) preparations and fungal culture of the lesions failed to demonstrate mycotic infection. There was no mention of PAS stain of skin biopsy specimens. In this case, the authors mentioned that EGR-like lesions preceded exacerbation of MF and questioned the prognostic significance of the EGR-like eruption in relation to MF.⁶

Holcomb et al⁷ reported the next case of a 75-year-old man with stage IIB MF (T3N0M0B0) with CD25⁺ and CD30⁺ large cell transformation who presented with an EGR-like eruption. In this case, PAS stain and KOH preparations were repeatedly negative for mycotic infection. Disease progression was not mentioned following the appearance of the EGR-like eruption.⁷

Nagase et al⁸ most recently described a case of a 73-year-old Japanese man with stage IB (T2N0M0B0) CD4⁻CD8⁻ MF and lung cancer who developed a cutaneous eruption mimicking EGR. Microscopy and culture excluded the presence of a mycotic infection. The patient achieved partial remission with photochemotherapy (psoralen plus UVA) combined with topical corticosteroids. No major changes in the patient’s skin lesions were noted following surgical resection of the lung cancer.⁸

Dermatophyte Infection
It is known that conventional tinea corporis can occur in the setting of CTCL. However, EGR-like eruptions in CTCL can be distinguished from standard tinea corporis by the classic morphology of EGR and clinical history of rapid migration of these characteristic lesions.

Tinea imbricata is known to have a clinical appearance that is similar to EGR, but the infection is caused by Tinea concentricum, which is limited to southwest Polynesia, Melanesia, Southeast Asia, India, and Central America. Although T rubrum was the dermatophyte isolated by Poonawalla et al,³ Jouary et al,⁵ and in our case, whether T rubrum infection in the setting of CTCL has any impact on prognosis needs further study.

Our case of an EGR-like eruption presented in a patient with SS and tinea corporis. Biopsy specimens showed CTCL and concomitant dermatophytic infection that was confirmed with PAS stain and identified as T rubrum. Interestingly, our patient’s EGR-like eruption cleared with oral terbinafine therapy, consistent with findings described by Poonawalla et al³ and Jouary et al⁵ in which treatment of the dermatophytic infection led to resolution of the EGR-like eruption, suggesting a causative role.

However, testing for dermatophytes was negative in the other reported cases of EGR-like eruptions in patients with MF, despite screening for the presence of fungal microorganisms using KOH preparation, PAS staining, or fungal culture, or a combination of these methods,^3-8 which raises the question: Do the cases reported without dermatophytic infection represent false-negative test results, or can the distinct clinical appearance of EGR indeed be seen in patients with CTCL who lack superimposed dermatophytosis? In 3 prior reported cases of EGR-like eruptions in MF, the eruption was preceded by immunosuppressive therapy.^5-7

Further investigation is needed to correlate the role of dermatophytic infection in EGR-like eruptions. Our case and the Jouary et al⁵ case reported dermatophyte-positive EGR-like eruptions in MF and SS detected with histopathologic analysis and PAS stain. This low-cost screening method should be considered in future cases. If the test result is dermatophyte positive, a 14-day course of oral terbinafine (250 mg/d) might induce resolution of the EGR-like eruption.

Conclusion

The role of dermatophyte-induced EGR or EGR-like eruptions in other settings also warrants further investigation to shed light on this poorly understood yet striking dermatologic condition. Our patient showed both MF and dermatophytes in skin biopsy results, regardless of whether those sites showed erythroderma or EGR-like features clinically. On 3 occasions, antifungal treatment cleared the EGR-like lesions and associated pruritus but not erythroderma. Therefore, it appears that the mere presence of dermatophytes was necessary but not sufficient to produce the EGR-like lesions observed in our case.

Case Report

A 65-year-old woman presented with stage IVA2 mycosis fungoides (MF)(T4N3M0B2)/Sézary syndrome (SS). A peripheral blood count contained 6000 Sézary cells with cerebriform nuclei, a CD2^+/−CD3⁺CD4⁺CD5^+/−CD7⁺CD8⁻CD26⁻immunophenotype, and a highly abnormal CD4 to CD8 ratio (70:1). Positron emission tomography and computed tomography demonstrated hypermetabolic subcutaneous nodules in the base of the neck and generalized lymphadenopathy. Lymph node biopsy showed involvement by T-cell lymphoma and dominant T-cell receptor γ clonality by polymerase chain reaction.

On initial presentation to the Cutaneous Lymphoma Clinic at the University of Wisconsin-Madison, the patient was erythrodermic. She also was noted to have undulating wavy bands and concentric annular, ringlike, thin, erythematous plaques with trailing scale, giving a wood grain, zebra hide–like appearance involving the buttocks, abdomen, and lower extremities (Figure 1). Lesions were markedly pruritic and were advancing rapidly. A diagnosis of erythema gyratum repens (EGR)–like eruption was made.

Interferon alfa-2b and methotrexate therapy was initiated. Additionally, oral terbinafine (250 mg/d) was initiated for 14 days, resulting in complete resolution of the EGR-like eruption; nevertheless, diffuse erythema remained. Subsequently, within 3 months of treatment, the cutaneous T-cell lymphoma (CTCL) improved with continued interferon alfa-2b and methotrexate. Erythroderma became minimal; the circulating Sézary cell count decreased by 50%. The patient ultimately had multiple relapses in erythroderma and progression of SS. Erythema gyratum repens–like lesions recurred on multiple occasions, with a temporary response to repeat courses of oral terbinafine.

Comment

Defining True EGR vs EGR-like Eruption
Sézary syndrome represents the leukemic stage of CTCL, which is defined by the triad of erythroderma; generalized lymphadenopathy; and neoplastic T cells in the skin, lymph nodes, and peripheral blood. It is well known that CTCL can mimic multiple benign and malignant dermatoses. One rare presentation of CTCL is an EGR-like eruption.

Erythema gyratum repens presents as rapidly advancing, erythematous, concentric bands that can be figurate, gyrate, or annular, with a fine trailing edge of scale (wood grain pattern). The diagnosis is based on the characteristic clinical pattern of EGR and by ruling out other mimicking conditions with biopsy.¹ Patients with the characteristic clinical pattern but with an alternate underlying dermatosis are described as having an EGR-like eruption rather than true EGR.

True EGR is most often but not always associated with underlying malignancy. Biopsy of true EGR eruptions show nonspecific histopathologic features, with perivascular superficial mononuclear dermatitis, occasional mild spongiosis, and focal parakeratosis; specific features of an alternate dermatosis are lacking.² In addition to CTCL, EGR-like eruptions have been described in a number of diseases, including systemic lupus erythematosus, erythema annulare centrifugum, bullous dermatosis, erythrokeratodermia variabilis, urticarial vasculitis, leukocytoclastic vasculitis, and neutrophilic dermatoses.

Prior Reports of EGR-like Eruption in Association With MF
According to a PubMed search of articles indexed for MEDLINE using the terms erythema gyratum repens in mycosis fungoides, mycosis fungoides with tinea, and concentric wood grain erythema, there have been 6 other cases of an EGR-like eruption in association with MF (Table). Poonawalla et al³ first described an EGR-like eruption (utilizing the term tinea pseudoimbricata) in a 55-year-old man with stage IB MF (T2N0M0B0). The patient had a preceding history of tinea pedis and tinea corporis that preceded the diagnosis of MF. At the time of MF diagnosis, the patient presented with extensive concentric, gyrate, wood grain, annular lesions. His MF was resistant to topical mechlorethamine, psoralen plus UVA, and oral bexarotene. The body surface area involvement decreased from 60% to less than 1% after institution of oral and topical antifungal therapy. It was postulated that the widespread dermatophytosis that preceded the development of MF may have been the persistent antigen leading to his disease. Preceding the diagnosis of MF, skin scrapings were floridly positive for dermatophyte hyphae. Fungal cultures from the affected areas of skin grew T rubrum.³

Moore et al⁴ described an EGR-like eruption on the trunk of a 73-year-old man with stage IA MF (T1N0M0B0). Biopsy was consistent with MF, but no fungal organisms were seen. Potassium hydroxide preparation and fungal cultures of the lesions also were negative for organisms. The patient was successfully treated with topical betamethasone.⁴Jouary et al⁵ described an EGR-like eruption in a 77-year-old man with stage III erythrodermic MF (T4N1M0B0). Biopsy showed mycelia on PAS stain. Subsequent culture isolated T rubrum. Terbinafine (250 mg/d) and ketoconazole cream 2% daily were initiated and the patient’s EGR-like rash quickly cleared, while MF progressed to SS.⁵

Cerri et al⁶ later described a case of EGR-like eruption in a 61-year-old man with stage I MF and an EGR-like eruption. Microscopic examination of potassium hydroxide (KOH) preparations and fungal culture of the lesions failed to demonstrate mycotic infection. There was no mention of PAS stain of skin biopsy specimens. In this case, the authors mentioned that EGR-like lesions preceded exacerbation of MF and questioned the prognostic significance of the EGR-like eruption in relation to MF.⁶

Holcomb et al⁷ reported the next case of a 75-year-old man with stage IIB MF (T3N0M0B0) with CD25⁺ and CD30⁺ large cell transformation who presented with an EGR-like eruption. In this case, PAS stain and KOH preparations were repeatedly negative for mycotic infection. Disease progression was not mentioned following the appearance of the EGR-like eruption.⁷

Nagase et al⁸ most recently described a case of a 73-year-old Japanese man with stage IB (T2N0M0B0) CD4⁻CD8⁻ MF and lung cancer who developed a cutaneous eruption mimicking EGR. Microscopy and culture excluded the presence of a mycotic infection. The patient achieved partial remission with photochemotherapy (psoralen plus UVA) combined with topical corticosteroids. No major changes in the patient’s skin lesions were noted following surgical resection of the lung cancer.⁸

Dermatophyte Infection
It is known that conventional tinea corporis can occur in the setting of CTCL. However, EGR-like eruptions in CTCL can be distinguished from standard tinea corporis by the classic morphology of EGR and clinical history of rapid migration of these characteristic lesions.

Tinea imbricata is known to have a clinical appearance that is similar to EGR, but the infection is caused by Tinea concentricum, which is limited to southwest Polynesia, Melanesia, Southeast Asia, India, and Central America. Although T rubrum was the dermatophyte isolated by Poonawalla et al,³ Jouary et al,⁵ and in our case, whether T rubrum infection in the setting of CTCL has any impact on prognosis needs further study.

Our case of an EGR-like eruption presented in a patient with SS and tinea corporis. Biopsy specimens showed CTCL and concomitant dermatophytic infection that was confirmed with PAS stain and identified as T rubrum. Interestingly, our patient’s EGR-like eruption cleared with oral terbinafine therapy, consistent with findings described by Poonawalla et al³ and Jouary et al⁵ in which treatment of the dermatophytic infection led to resolution of the EGR-like eruption, suggesting a causative role.

However, testing for dermatophytes was negative in the other reported cases of EGR-like eruptions in patients with MF, despite screening for the presence of fungal microorganisms using KOH preparation, PAS staining, or fungal culture, or a combination of these methods,^3-8 which raises the question: Do the cases reported without dermatophytic infection represent false-negative test results, or can the distinct clinical appearance of EGR indeed be seen in patients with CTCL who lack superimposed dermatophytosis? In 3 prior reported cases of EGR-like eruptions in MF, the eruption was preceded by immunosuppressive therapy.^5-7

Further investigation is needed to correlate the role of dermatophytic infection in EGR-like eruptions. Our case and the Jouary et al⁵ case reported dermatophyte-positive EGR-like eruptions in MF and SS detected with histopathologic analysis and PAS stain. This low-cost screening method should be considered in future cases. If the test result is dermatophyte positive, a 14-day course of oral terbinafine (250 mg/d) might induce resolution of the EGR-like eruption.

Conclusion

The role of dermatophyte-induced EGR or EGR-like eruptions in other settings also warrants further investigation to shed light on this poorly understood yet striking dermatologic condition. Our patient showed both MF and dermatophytes in skin biopsy results, regardless of whether those sites showed erythroderma or EGR-like features clinically. On 3 occasions, antifungal treatment cleared the EGR-like lesions and associated pruritus but not erythroderma. Therefore, it appears that the mere presence of dermatophytes was necessary but not sufficient to produce the EGR-like lesions observed in our case.

To the Editor:

A 30-year-old man with no notable medical history presented to the dermatology clinic with multiple subcutaneous nodules on the forehead of 5 years’ duration. He reported no history of forehead trauma or manipulation of the lesions, and there was no accompanying pruritis, pain, erythema, or purulent discharge. There was no family history of skin or gastrointestinal tract tumors. On physical examination, the patient had 5 firm, flesh-colored to yellow nodules measuring approximately 0.2 to 1.5 cm in diameter without central punctae scattered over the central forehead (Figure 1). Due to cosmetic concerns, the patient elected to pursue surgical excision of the lesions, which occurred over several office visits. During surgical excision, the lesions were found to be smooth, encapsulated, and mobile, and they were excised without surgical complication. Histopathologic examination showed subcutaneous cysts lined by squamous epithelium with associated sebaceous glands (Figure 2A) and hair follicles in the cyst lumen (Figure 2B). These findings confirmed the diagnosis of multiple subcutaneous dermoid cysts.

Dermoid cysts are relatively uncommon, benign tumors consisting of tissue derived from ectodermal and mesodermal germ cell layers. Dermoid cysts may be distinguished from teratomas, which may contain tissues derived from all 3 germ cell layers and typically consist of types of tissues foreign to the site of origin, such as dental, thyroid, gastrointestinal, or neural tissue.^1,2 The majority of dermoid cysts are congenitally developed along the lines of embryologic fusion due to an error in the division of the ectoderm and mesoderm^3,4; however, some dermoid cysts may be acquired from epidermal elements being traumatically implanted into the dermis.⁵

Our patient’s presentation with multiple dermoid cysts was atypical, as dermoid cysts are almost always solitary tumors. A similar case was reported in a 41-year-old man who developed multiple dermoid cysts on the forehead over a 20-year period.This patient also was otherwise healthy, denied prior trauma to the forehead, and reported no family history of skin or gastrointestinal tract tumors.⁵

Another unusual feature in our case was the location of the dermoid cysts on the central forehead. The most common location for dermoid cysts is the lateral third of the eyebrows (47%–70% of cases).^1,4,6-10 These cysts occur because of sequestration of the surface ectoderm during fusion along the naso-optic groove.² Dermoid cysts also have been noted in other anatomical areas such as the scalp, nose, anterior neck, and trunk.⁶

Dermoid cysts tend to be small, round, smooth, and slowly growing until sudden enlargement prompts surgical evaluation.^4,6 During surgical excision, they often are fixed to the underlying bone but also may be freely mobile, as in our patient.⁶ Histopathologic examination reveals a stratified squamous epithelium with associated adnexal structures such as sebaceous glands or hair follicles.¹ Smooth muscle fibers, prominent vascular stroma, small nerves, and collagen and elastic fibers also may be found within the lumen of dermoid cysts.²

In some cases, dermoid cysts may be invasive and carry the risk of bony erosion, intracranial extension, osteomyelitis, meningitis, or cerebral abscess. Imaging studies sometimes are needed to rule out intracranial or intraspinal extension, particularly for midline dermoid cysts.⁶ The standard of treatment for dermoid cysts is surgical excision and complete enucleation without disruption of the cyst wall; however, invasive dermoid cysts may require endoscopic excision, orbitotomy, or craniotomy.^4,6

To the Editor:

A 30-year-old man with no notable medical history presented to the dermatology clinic with multiple subcutaneous nodules on the forehead of 5 years’ duration. He reported no history of forehead trauma or manipulation of the lesions, and there was no accompanying pruritis, pain, erythema, or purulent discharge. There was no family history of skin or gastrointestinal tract tumors. On physical examination, the patient had 5 firm, flesh-colored to yellow nodules measuring approximately 0.2 to 1.5 cm in diameter without central punctae scattered over the central forehead (Figure 1). Due to cosmetic concerns, the patient elected to pursue surgical excision of the lesions, which occurred over several office visits. During surgical excision, the lesions were found to be smooth, encapsulated, and mobile, and they were excised without surgical complication. Histopathologic examination showed subcutaneous cysts lined by squamous epithelium with associated sebaceous glands (Figure 2A) and hair follicles in the cyst lumen (Figure 2B). These findings confirmed the diagnosis of multiple subcutaneous dermoid cysts.

Dermoid cysts are relatively uncommon, benign tumors consisting of tissue derived from ectodermal and mesodermal germ cell layers. Dermoid cysts may be distinguished from teratomas, which may contain tissues derived from all 3 germ cell layers and typically consist of types of tissues foreign to the site of origin, such as dental, thyroid, gastrointestinal, or neural tissue.^1,2 The majority of dermoid cysts are congenitally developed along the lines of embryologic fusion due to an error in the division of the ectoderm and mesoderm^3,4; however, some dermoid cysts may be acquired from epidermal elements being traumatically implanted into the dermis.⁵

Our patient’s presentation with multiple dermoid cysts was atypical, as dermoid cysts are almost always solitary tumors. A similar case was reported in a 41-year-old man who developed multiple dermoid cysts on the forehead over a 20-year period.This patient also was otherwise healthy, denied prior trauma to the forehead, and reported no family history of skin or gastrointestinal tract tumors.⁵

Another unusual feature in our case was the location of the dermoid cysts on the central forehead. The most common location for dermoid cysts is the lateral third of the eyebrows (47%–70% of cases).^1,4,6-10 These cysts occur because of sequestration of the surface ectoderm during fusion along the naso-optic groove.² Dermoid cysts also have been noted in other anatomical areas such as the scalp, nose, anterior neck, and trunk.⁶

Dermoid cysts tend to be small, round, smooth, and slowly growing until sudden enlargement prompts surgical evaluation.^4,6 During surgical excision, they often are fixed to the underlying bone but also may be freely mobile, as in our patient.⁶ Histopathologic examination reveals a stratified squamous epithelium with associated adnexal structures such as sebaceous glands or hair follicles.¹ Smooth muscle fibers, prominent vascular stroma, small nerves, and collagen and elastic fibers also may be found within the lumen of dermoid cysts.²

In some cases, dermoid cysts may be invasive and carry the risk of bony erosion, intracranial extension, osteomyelitis, meningitis, or cerebral abscess. Imaging studies sometimes are needed to rule out intracranial or intraspinal extension, particularly for midline dermoid cysts.⁶ The standard of treatment for dermoid cysts is surgical excision and complete enucleation without disruption of the cyst wall; however, invasive dermoid cysts may require endoscopic excision, orbitotomy, or craniotomy.^4,6

To the Editor:

A 30-year-old man with no notable medical history presented to the dermatology clinic with multiple subcutaneous nodules on the forehead of 5 years’ duration. He reported no history of forehead trauma or manipulation of the lesions, and there was no accompanying pruritis, pain, erythema, or purulent discharge. There was no family history of skin or gastrointestinal tract tumors. On physical examination, the patient had 5 firm, flesh-colored to yellow nodules measuring approximately 0.2 to 1.5 cm in diameter without central punctae scattered over the central forehead (Figure 1). Due to cosmetic concerns, the patient elected to pursue surgical excision of the lesions, which occurred over several office visits. During surgical excision, the lesions were found to be smooth, encapsulated, and mobile, and they were excised without surgical complication. Histopathologic examination showed subcutaneous cysts lined by squamous epithelium with associated sebaceous glands (Figure 2A) and hair follicles in the cyst lumen (Figure 2B). These findings confirmed the diagnosis of multiple subcutaneous dermoid cysts.

Dermoid cysts are relatively uncommon, benign tumors consisting of tissue derived from ectodermal and mesodermal germ cell layers. Dermoid cysts may be distinguished from teratomas, which may contain tissues derived from all 3 germ cell layers and typically consist of types of tissues foreign to the site of origin, such as dental, thyroid, gastrointestinal, or neural tissue.^1,2 The majority of dermoid cysts are congenitally developed along the lines of embryologic fusion due to an error in the division of the ectoderm and mesoderm^3,4; however, some dermoid cysts may be acquired from epidermal elements being traumatically implanted into the dermis.⁵

Our patient’s presentation with multiple dermoid cysts was atypical, as dermoid cysts are almost always solitary tumors. A similar case was reported in a 41-year-old man who developed multiple dermoid cysts on the forehead over a 20-year period.This patient also was otherwise healthy, denied prior trauma to the forehead, and reported no family history of skin or gastrointestinal tract tumors.⁵

Another unusual feature in our case was the location of the dermoid cysts on the central forehead. The most common location for dermoid cysts is the lateral third of the eyebrows (47%–70% of cases).^1,4,6-10 These cysts occur because of sequestration of the surface ectoderm during fusion along the naso-optic groove.² Dermoid cysts also have been noted in other anatomical areas such as the scalp, nose, anterior neck, and trunk.⁶

Dermoid cysts tend to be small, round, smooth, and slowly growing until sudden enlargement prompts surgical evaluation.^4,6 During surgical excision, they often are fixed to the underlying bone but also may be freely mobile, as in our patient.⁶ Histopathologic examination reveals a stratified squamous epithelium with associated adnexal structures such as sebaceous glands or hair follicles.¹ Smooth muscle fibers, prominent vascular stroma, small nerves, and collagen and elastic fibers also may be found within the lumen of dermoid cysts.²

In some cases, dermoid cysts may be invasive and carry the risk of bony erosion, intracranial extension, osteomyelitis, meningitis, or cerebral abscess. Imaging studies sometimes are needed to rule out intracranial or intraspinal extension, particularly for midline dermoid cysts.⁶ The standard of treatment for dermoid cysts is surgical excision and complete enucleation without disruption of the cyst wall; however, invasive dermoid cysts may require endoscopic excision, orbitotomy, or craniotomy.^4,6

An atypical case of cutaneous mantle cell lymphoma (MCL) with histomorphological features mimicking subcutaneous panniculitis-like T-cell lymphoma (SPTCL) highlights a “potential pitfall,” according to investigators.

This unusual case stresses the importance of molecular cytogenetics and/or immunohistochemistry for panniculitis-type lymphomas, reported lead author Caroline Laggis, MD of the University of Utah, Salt Lake City, and colleagues.

“While morphologic features of SPTCL, specifically rimming of adipocytes by neoplastic lymphoid cells, have been documented in other types of lymphomas, this case is exceptional in that the morphologic features of SPTCL are showed in secondary cutaneous involvement by MCL,” the investigators wrote. Their report is in Journal of Cutaneous Pathology.

The patient was a 69-year-old man who presented with 2-year history of night sweats and fever of unknown origin, and, closer to presentation, weight loss and tender bumps under the skin of his pelvic region.

Subsequent computed tomography and excisional lymph node biopsy led to a diagnosis of MCL, with a Mantle Cell Lymphoma International Prognostic Index of 5, suggesting aggressive, intermediate-risk disease. Further imaging showed involvement of the nasopharynx, and cervical and mediastinal lymph nodes.

Bendamustine and rituximab chemotherapy was given unremarkably until the final cycle, at which point the patient presented with tender subcutaneous nodules on his lower legs. Histopathology from punch biopsies revealed “a dense infiltrate of monomorphic, mitotically active lymphoid cells with infiltration between the deep dermal collagen and the adipocytes in subcutaneous fat,” the investigators wrote, noting that the infiltrative cells were blastoid and 70% expressed cyclin D1, supporting cutaneous involvement of his systemic MCL.

Treatment was switched to ibrutinib and selinexor via a clinical trial, which led to temporary improvement of leg lesions; when the lesions returned, biopsy was performed with the same histopathological result. Lenalidomide and rituximab were started, but without success, and disease spread to the central nervous system.

Another biopsy of the skin lesions again supported cutaneous MCL, with tumor cells rimming individual adipocytes.

Because of this atypical morphology, fluorescence in situ hybridization (FISH) was conducted, revealing t(11;14)(q13:32) positivity, thereby “confirming the diagnosis of cutaneous involvement by systemic MCL,” the investigators wrote.

Genomic sequencing revealed abnormalities of “ataxia-telangiectasia mutated, mechanistic target of rapamycin kinase (mTOR), BCL6 corepressor, and FAS-associated factor 1, as well as the expected mutation in IGH-CCND1, leading to cyclin D1 upregulation.”

Subsequent treatment was unsuccessful, and the patient died from his disease.

“The complex and central role that mTOR plays in adipose homeostasis may link our tumor to its preference to the adipose tissue, although further investigation is warranted regarding specific genomic alterations in lymphomas and the implications these mutations have in the involvement of tumor cells with cutaneous and adipose environments,” the investigators wrote.

The investigators did not report conflicts of interest.

SOURCE: Laggis C et al. 2019 Apr 8. doi:10.1111/cup.13471.

An atypical case of cutaneous mantle cell lymphoma (MCL) with histomorphological features mimicking subcutaneous panniculitis-like T-cell lymphoma (SPTCL) highlights a “potential pitfall,” according to investigators.

This unusual case stresses the importance of molecular cytogenetics and/or immunohistochemistry for panniculitis-type lymphomas, reported lead author Caroline Laggis, MD of the University of Utah, Salt Lake City, and colleagues.

“While morphologic features of SPTCL, specifically rimming of adipocytes by neoplastic lymphoid cells, have been documented in other types of lymphomas, this case is exceptional in that the morphologic features of SPTCL are showed in secondary cutaneous involvement by MCL,” the investigators wrote. Their report is in Journal of Cutaneous Pathology.

The patient was a 69-year-old man who presented with 2-year history of night sweats and fever of unknown origin, and, closer to presentation, weight loss and tender bumps under the skin of his pelvic region.

Subsequent computed tomography and excisional lymph node biopsy led to a diagnosis of MCL, with a Mantle Cell Lymphoma International Prognostic Index of 5, suggesting aggressive, intermediate-risk disease. Further imaging showed involvement of the nasopharynx, and cervical and mediastinal lymph nodes.

Bendamustine and rituximab chemotherapy was given unremarkably until the final cycle, at which point the patient presented with tender subcutaneous nodules on his lower legs. Histopathology from punch biopsies revealed “a dense infiltrate of monomorphic, mitotically active lymphoid cells with infiltration between the deep dermal collagen and the adipocytes in subcutaneous fat,” the investigators wrote, noting that the infiltrative cells were blastoid and 70% expressed cyclin D1, supporting cutaneous involvement of his systemic MCL.

Treatment was switched to ibrutinib and selinexor via a clinical trial, which led to temporary improvement of leg lesions; when the lesions returned, biopsy was performed with the same histopathological result. Lenalidomide and rituximab were started, but without success, and disease spread to the central nervous system.

Another biopsy of the skin lesions again supported cutaneous MCL, with tumor cells rimming individual adipocytes.

Because of this atypical morphology, fluorescence in situ hybridization (FISH) was conducted, revealing t(11;14)(q13:32) positivity, thereby “confirming the diagnosis of cutaneous involvement by systemic MCL,” the investigators wrote.

Genomic sequencing revealed abnormalities of “ataxia-telangiectasia mutated, mechanistic target of rapamycin kinase (mTOR), BCL6 corepressor, and FAS-associated factor 1, as well as the expected mutation in IGH-CCND1, leading to cyclin D1 upregulation.”

Subsequent treatment was unsuccessful, and the patient died from his disease.

“The complex and central role that mTOR plays in adipose homeostasis may link our tumor to its preference to the adipose tissue, although further investigation is warranted regarding specific genomic alterations in lymphomas and the implications these mutations have in the involvement of tumor cells with cutaneous and adipose environments,” the investigators wrote.

The investigators did not report conflicts of interest.

SOURCE: Laggis C et al. 2019 Apr 8. doi:10.1111/cup.13471.

An atypical case of cutaneous mantle cell lymphoma (MCL) with histomorphological features mimicking subcutaneous panniculitis-like T-cell lymphoma (SPTCL) highlights a “potential pitfall,” according to investigators.

This unusual case stresses the importance of molecular cytogenetics and/or immunohistochemistry for panniculitis-type lymphomas, reported lead author Caroline Laggis, MD of the University of Utah, Salt Lake City, and colleagues.

“While morphologic features of SPTCL, specifically rimming of adipocytes by neoplastic lymphoid cells, have been documented in other types of lymphomas, this case is exceptional in that the morphologic features of SPTCL are showed in secondary cutaneous involvement by MCL,” the investigators wrote. Their report is in Journal of Cutaneous Pathology.

The patient was a 69-year-old man who presented with 2-year history of night sweats and fever of unknown origin, and, closer to presentation, weight loss and tender bumps under the skin of his pelvic region.

Subsequent computed tomography and excisional lymph node biopsy led to a diagnosis of MCL, with a Mantle Cell Lymphoma International Prognostic Index of 5, suggesting aggressive, intermediate-risk disease. Further imaging showed involvement of the nasopharynx, and cervical and mediastinal lymph nodes.

Bendamustine and rituximab chemotherapy was given unremarkably until the final cycle, at which point the patient presented with tender subcutaneous nodules on his lower legs. Histopathology from punch biopsies revealed “a dense infiltrate of monomorphic, mitotically active lymphoid cells with infiltration between the deep dermal collagen and the adipocytes in subcutaneous fat,” the investigators wrote, noting that the infiltrative cells were blastoid and 70% expressed cyclin D1, supporting cutaneous involvement of his systemic MCL.

Treatment was switched to ibrutinib and selinexor via a clinical trial, which led to temporary improvement of leg lesions; when the lesions returned, biopsy was performed with the same histopathological result. Lenalidomide and rituximab were started, but without success, and disease spread to the central nervous system.

Another biopsy of the skin lesions again supported cutaneous MCL, with tumor cells rimming individual adipocytes.

Because of this atypical morphology, fluorescence in situ hybridization (FISH) was conducted, revealing t(11;14)(q13:32) positivity, thereby “confirming the diagnosis of cutaneous involvement by systemic MCL,” the investigators wrote.

Genomic sequencing revealed abnormalities of “ataxia-telangiectasia mutated, mechanistic target of rapamycin kinase (mTOR), BCL6 corepressor, and FAS-associated factor 1, as well as the expected mutation in IGH-CCND1, leading to cyclin D1 upregulation.”

Subsequent treatment was unsuccessful, and the patient died from his disease.

“The complex and central role that mTOR plays in adipose homeostasis may link our tumor to its preference to the adipose tissue, although further investigation is warranted regarding specific genomic alterations in lymphomas and the implications these mutations have in the involvement of tumor cells with cutaneous and adipose environments,” the investigators wrote.

The investigators did not report conflicts of interest.

SOURCE: Laggis C et al. 2019 Apr 8. doi:10.1111/cup.13471.

The Diagnosis: Metastatic Adenocarcinoma of the Colon 

Cutaneous adenocarcinomas are uncommon, whether they present as a primary lesion or metastatic disease. In our patient, the histologic findings and immunohistochemical staining pattern were consistent with metastatic adenocarcinoma of the colon, an uncommon clinical presentation.  

Colonic adenocarcinoma can cause cutaneous metastasis in 3% of cases. The most common sites of metastases include the abdomen, chest, and back.¹ On histologic examination, hematoxylin and eosin (H&E)-stained sections of cutaneous metastatic adenocarcinoma illustrate a malignant gland-forming neoplasm in the dermis with luminal mucin and necrotic debris (quiz image). The glands are lined by tall columnar epithelial cells with hyperchromatic nuclei. Alternatively, poorly differentiated morphology can be seen with fewer glands and more infiltrating nests of tumor cells.² Immunohistochemically, colonic adenocarcinoma typically is negative for cytokeratin (CK) 7 and positive for CK20 and caudal type homeobox transcription factor 2 (CDX-2).³  

Primary cutaneous mucinous carcinoma is characterized by islands of neoplastic cells floating in pools of mucin (Figure 1). It may be indistinguishable from metastatic mucinous carcinomas of the colon or breast. Immunohistochemistry can be helpful in differentiating metastatic breast vs colon carcinoma. Cytokeratin 7, GATA binding protein 3, gross cystic disease fluid protein 15, and estrogen receptor will be positive in carcinomas of the breast and will be negative in colonic adenocarcinomas.^4-6 Furthermore, lesional cells in metastatic adenocarcinoma of the colon are positive for CDX-2 and CK20, while those in metastatic carcinoma of the breast are negative.² Immunohistochemistry also can differentiate primary cutaneous carcinoma from metastatic adenocarcinoma. When used in combination, p63 and podoplanin (D2-40) offer a highly sensitive and specific indicator of a primary cutaneous neoplasm, as both demonstrate either focal or diffuse positivity in this setting. In contrast, these stains typically are negative in metastatic adenocarcinomas of the skin.⁷ 

Endometriosis affects 1% to 2% of all reproductive-age females, of which extrapelvic manifestations account for only 0.5% to 1.0% of cases.⁸ Histologically, extrapelvic endometriosis is characterized by the triad of endometrial-type glands, endometrial stroma, and hemorrhage or hemosiderin deposition (Figure 2). The glands can enlarge and demonstrate architectural distortion with partial lack of polarity. These features initially can be concerning for adenocarcinoma, but on closer examination, nuclear morphology is regular and mitoses are absent.^8,9 The diagnosis usually can be rendered with H&E alone; however, immunohistochemical stains for CD10 and estrogen receptor can highlight the endometrial stroma.¹⁰ Furthermore, endometrial glands will stain positive for paired box gene 8 (PAX8), a marker that is not expressed within the gastrointestinal tract and associated malignancies.¹¹  

Primary cutaneous angiosarcoma may mimic adenocarcinoma, as the endothelial-lined vessels can be confused as malignant glands (Figure 3). Angiosarcoma often is seen in 1 of 3 clinical presentations: the head and neck of elderly patients, postradiation treatment, and chronic lymphedema.^12,13 Regardless of the location, the disease carries a poor prognosis, with a 5-year survival rate of 12% following initial diagnosis.¹³ Angiosarcoma is characterized by malignant endothelial cells dissecting through the dermis. Although the histology can be deceptively bland in some cases, the neoplasm most commonly demonstrates notable atypia with a multilayered endothelium and occasional intravascular atypical cells ("fish in the creek appearance").^13,14 There can be frequent mitoses, and the atypical cells may show intracytoplasmic lumina containing red blood cells. The lesional cells are positive for endothelial markers such as erythroblast transformation specific related gene (ERG), CD31, CD34, and friend leukemia integration factor 1 (FLI-1).^15,16  

Breast cancer also can cause cutaneous metastases in approximately 20% of cases, with the most common presenting site being the anterior chest wall.¹⁷ Macroscopically, these lesions appear most commonly as painless nodules but also as telangiectatic, erysipeloid, fibrotic, and alopecic lesions.^17-19 The histologic findings from H&E-stained sections of a cutaneous metastasis of breast cancer are variable and depend on the specific tumor subtype (eg, ductal, lobular, mucinous). However, the classic histologic presentation is that of nests and cords of malignant epithelial cells with variable gland formation. Often, tumor cells infiltrate in a single-file fashion (Figure 4).¹⁷ Although inflammatory breast carcinoma is a strictly clinical diagnosis, the presence of tumor cells in the lymphovascular spaces is a histologic clue to this diagnosis. Immunohistochemically, GATA binding protein 3 is helpful in identifying both hormone receptor-positive and -negative breast cancer subtypes that have metastasized.²⁰ 

Within the histologic differential diagnoses, the most useful tool to diagnose metastatic adenocarcinoma of the colon often is a thorough clinical history. In the absence of a clinical history of adenocarcinoma, immunohistochemistry can be a useful adjunct to aid in the correct characterization and classification of a malignant gland-forming tumor.^2,3,6 

The Diagnosis: Metastatic Adenocarcinoma of the Colon 

Cutaneous adenocarcinomas are uncommon, whether they present as a primary lesion or metastatic disease. In our patient, the histologic findings and immunohistochemical staining pattern were consistent with metastatic adenocarcinoma of the colon, an uncommon clinical presentation.  

Colonic adenocarcinoma can cause cutaneous metastasis in 3% of cases. The most common sites of metastases include the abdomen, chest, and back.¹ On histologic examination, hematoxylin and eosin (H&E)-stained sections of cutaneous metastatic adenocarcinoma illustrate a malignant gland-forming neoplasm in the dermis with luminal mucin and necrotic debris (quiz image). The glands are lined by tall columnar epithelial cells with hyperchromatic nuclei. Alternatively, poorly differentiated morphology can be seen with fewer glands and more infiltrating nests of tumor cells.² Immunohistochemically, colonic adenocarcinoma typically is negative for cytokeratin (CK) 7 and positive for CK20 and caudal type homeobox transcription factor 2 (CDX-2).³  

Primary cutaneous mucinous carcinoma is characterized by islands of neoplastic cells floating in pools of mucin (Figure 1). It may be indistinguishable from metastatic mucinous carcinomas of the colon or breast. Immunohistochemistry can be helpful in differentiating metastatic breast vs colon carcinoma. Cytokeratin 7, GATA binding protein 3, gross cystic disease fluid protein 15, and estrogen receptor will be positive in carcinomas of the breast and will be negative in colonic adenocarcinomas.^4-6 Furthermore, lesional cells in metastatic adenocarcinoma of the colon are positive for CDX-2 and CK20, while those in metastatic carcinoma of the breast are negative.² Immunohistochemistry also can differentiate primary cutaneous carcinoma from metastatic adenocarcinoma. When used in combination, p63 and podoplanin (D2-40) offer a highly sensitive and specific indicator of a primary cutaneous neoplasm, as both demonstrate either focal or diffuse positivity in this setting. In contrast, these stains typically are negative in metastatic adenocarcinomas of the skin.⁷ 

Endometriosis affects 1% to 2% of all reproductive-age females, of which extrapelvic manifestations account for only 0.5% to 1.0% of cases.⁸ Histologically, extrapelvic endometriosis is characterized by the triad of endometrial-type glands, endometrial stroma, and hemorrhage or hemosiderin deposition (Figure 2). The glands can enlarge and demonstrate architectural distortion with partial lack of polarity. These features initially can be concerning for adenocarcinoma, but on closer examination, nuclear morphology is regular and mitoses are absent.^8,9 The diagnosis usually can be rendered with H&E alone; however, immunohistochemical stains for CD10 and estrogen receptor can highlight the endometrial stroma.¹⁰ Furthermore, endometrial glands will stain positive for paired box gene 8 (PAX8), a marker that is not expressed within the gastrointestinal tract and associated malignancies.¹¹  

Primary cutaneous angiosarcoma may mimic adenocarcinoma, as the endothelial-lined vessels can be confused as malignant glands (Figure 3). Angiosarcoma often is seen in 1 of 3 clinical presentations: the head and neck of elderly patients, postradiation treatment, and chronic lymphedema.^12,13 Regardless of the location, the disease carries a poor prognosis, with a 5-year survival rate of 12% following initial diagnosis.¹³ Angiosarcoma is characterized by malignant endothelial cells dissecting through the dermis. Although the histology can be deceptively bland in some cases, the neoplasm most commonly demonstrates notable atypia with a multilayered endothelium and occasional intravascular atypical cells ("fish in the creek appearance").^13,14 There can be frequent mitoses, and the atypical cells may show intracytoplasmic lumina containing red blood cells. The lesional cells are positive for endothelial markers such as erythroblast transformation specific related gene (ERG), CD31, CD34, and friend leukemia integration factor 1 (FLI-1).^15,16  

Breast cancer also can cause cutaneous metastases in approximately 20% of cases, with the most common presenting site being the anterior chest wall.¹⁷ Macroscopically, these lesions appear most commonly as painless nodules but also as telangiectatic, erysipeloid, fibrotic, and alopecic lesions.^17-19 The histologic findings from H&E-stained sections of a cutaneous metastasis of breast cancer are variable and depend on the specific tumor subtype (eg, ductal, lobular, mucinous). However, the classic histologic presentation is that of nests and cords of malignant epithelial cells with variable gland formation. Often, tumor cells infiltrate in a single-file fashion (Figure 4).¹⁷ Although inflammatory breast carcinoma is a strictly clinical diagnosis, the presence of tumor cells in the lymphovascular spaces is a histologic clue to this diagnosis. Immunohistochemically, GATA binding protein 3 is helpful in identifying both hormone receptor-positive and -negative breast cancer subtypes that have metastasized.²⁰ 

Within the histologic differential diagnoses, the most useful tool to diagnose metastatic adenocarcinoma of the colon often is a thorough clinical history. In the absence of a clinical history of adenocarcinoma, immunohistochemistry can be a useful adjunct to aid in the correct characterization and classification of a malignant gland-forming tumor.^2,3,6 

The Diagnosis: Metastatic Adenocarcinoma of the Colon 

Cutaneous adenocarcinomas are uncommon, whether they present as a primary lesion or metastatic disease. In our patient, the histologic findings and immunohistochemical staining pattern were consistent with metastatic adenocarcinoma of the colon, an uncommon clinical presentation.  

Colonic adenocarcinoma can cause cutaneous metastasis in 3% of cases. The most common sites of metastases include the abdomen, chest, and back.¹ On histologic examination, hematoxylin and eosin (H&E)-stained sections of cutaneous metastatic adenocarcinoma illustrate a malignant gland-forming neoplasm in the dermis with luminal mucin and necrotic debris (quiz image). The glands are lined by tall columnar epithelial cells with hyperchromatic nuclei. Alternatively, poorly differentiated morphology can be seen with fewer glands and more infiltrating nests of tumor cells.² Immunohistochemically, colonic adenocarcinoma typically is negative for cytokeratin (CK) 7 and positive for CK20 and caudal type homeobox transcription factor 2 (CDX-2).³  

Primary cutaneous mucinous carcinoma is characterized by islands of neoplastic cells floating in pools of mucin (Figure 1). It may be indistinguishable from metastatic mucinous carcinomas of the colon or breast. Immunohistochemistry can be helpful in differentiating metastatic breast vs colon carcinoma. Cytokeratin 7, GATA binding protein 3, gross cystic disease fluid protein 15, and estrogen receptor will be positive in carcinomas of the breast and will be negative in colonic adenocarcinomas.^4-6 Furthermore, lesional cells in metastatic adenocarcinoma of the colon are positive for CDX-2 and CK20, while those in metastatic carcinoma of the breast are negative.² Immunohistochemistry also can differentiate primary cutaneous carcinoma from metastatic adenocarcinoma. When used in combination, p63 and podoplanin (D2-40) offer a highly sensitive and specific indicator of a primary cutaneous neoplasm, as both demonstrate either focal or diffuse positivity in this setting. In contrast, these stains typically are negative in metastatic adenocarcinomas of the skin.⁷ 

Endometriosis affects 1% to 2% of all reproductive-age females, of which extrapelvic manifestations account for only 0.5% to 1.0% of cases.⁸ Histologically, extrapelvic endometriosis is characterized by the triad of endometrial-type glands, endometrial stroma, and hemorrhage or hemosiderin deposition (Figure 2). The glands can enlarge and demonstrate architectural distortion with partial lack of polarity. These features initially can be concerning for adenocarcinoma, but on closer examination, nuclear morphology is regular and mitoses are absent.^8,9 The diagnosis usually can be rendered with H&E alone; however, immunohistochemical stains for CD10 and estrogen receptor can highlight the endometrial stroma.¹⁰ Furthermore, endometrial glands will stain positive for paired box gene 8 (PAX8), a marker that is not expressed within the gastrointestinal tract and associated malignancies.¹¹  

Primary cutaneous angiosarcoma may mimic adenocarcinoma, as the endothelial-lined vessels can be confused as malignant glands (Figure 3). Angiosarcoma often is seen in 1 of 3 clinical presentations: the head and neck of elderly patients, postradiation treatment, and chronic lymphedema.^12,13 Regardless of the location, the disease carries a poor prognosis, with a 5-year survival rate of 12% following initial diagnosis.¹³ Angiosarcoma is characterized by malignant endothelial cells dissecting through the dermis. Although the histology can be deceptively bland in some cases, the neoplasm most commonly demonstrates notable atypia with a multilayered endothelium and occasional intravascular atypical cells ("fish in the creek appearance").^13,14 There can be frequent mitoses, and the atypical cells may show intracytoplasmic lumina containing red blood cells. The lesional cells are positive for endothelial markers such as erythroblast transformation specific related gene (ERG), CD31, CD34, and friend leukemia integration factor 1 (FLI-1).^15,16  

Breast cancer also can cause cutaneous metastases in approximately 20% of cases, with the most common presenting site being the anterior chest wall.¹⁷ Macroscopically, these lesions appear most commonly as painless nodules but also as telangiectatic, erysipeloid, fibrotic, and alopecic lesions.^17-19 The histologic findings from H&E-stained sections of a cutaneous metastasis of breast cancer are variable and depend on the specific tumor subtype (eg, ductal, lobular, mucinous). However, the classic histologic presentation is that of nests and cords of malignant epithelial cells with variable gland formation. Often, tumor cells infiltrate in a single-file fashion (Figure 4).¹⁷ Although inflammatory breast carcinoma is a strictly clinical diagnosis, the presence of tumor cells in the lymphovascular spaces is a histologic clue to this diagnosis. Immunohistochemically, GATA binding protein 3 is helpful in identifying both hormone receptor-positive and -negative breast cancer subtypes that have metastasized.²⁰ 

Within the histologic differential diagnoses, the most useful tool to diagnose metastatic adenocarcinoma of the colon often is a thorough clinical history. In the absence of a clinical history of adenocarcinoma, immunohistochemistry can be a useful adjunct to aid in the correct characterization and classification of a malignant gland-forming tumor.^2,3,6 

To the Editor:

Lichen amyloidosis (LA) classically presents as a pruritic, hyperkeratotic, papular eruption localized to the pretibial surface of the legs.¹ Nonpruritic and generalized variants have been reported but are rare.² Although it is the most common subtype of primary localized cutaneous amyloidosis, LA is a benign condition but is difficult to eradicate.¹ The precise pathophysiology is poorly understood, but chronic frictional irritation is closely associated with the eruption. We present a nongeneralized case of LA in an atypical location.

A healthy 30-year-old woman presented with an intermittent itchy rash on the elbows and knees of 2 years’ duration. The patient was first diagnosed with lichen simplex chronicus (LSC) and initially responded well to treatment with fluocinonide ointment 0.05%. Nearly 2 years after the initial presentation, she developed recurrent symptoms and sought further treatment. She reported frequent scratching in association with episodes of anxiety. Examination revealed numerous 1- to 3-mm, flesh-colored to light brown, monomorphic, dome-shaped papules over the extensor surfaces of the bilateral arms and left pretibial surface (Figure 1).

^4-6

The possibility remains that this patient first presented with LSC 2 years prior and secondarily developed LA due to chronic trauma. Indeed, LA has been proposed as a variant of LSC. In both conditions, scratching seems to be the most important factor in the development of lesions. It has been proposed that treatment should primarily focus on the amelioration of pruritus.⁵

Five percent to 10% of cases of LA have been found to have some form of upper extremity involvement.⁷ However, these cases typically are associated with a generalized presentation involving the trunk and arms.^2,7 Our patient had no evidence of disease elsewhere. When evaluating a localized, pruritic, monomorphic, papular eruption on the extensor surfaces of the arms, LA may be an important consideration.

To the Editor:

Lichen amyloidosis (LA) classically presents as a pruritic, hyperkeratotic, papular eruption localized to the pretibial surface of the legs.¹ Nonpruritic and generalized variants have been reported but are rare.² Although it is the most common subtype of primary localized cutaneous amyloidosis, LA is a benign condition but is difficult to eradicate.¹ The precise pathophysiology is poorly understood, but chronic frictional irritation is closely associated with the eruption. We present a nongeneralized case of LA in an atypical location.

A healthy 30-year-old woman presented with an intermittent itchy rash on the elbows and knees of 2 years’ duration. The patient was first diagnosed with lichen simplex chronicus (LSC) and initially responded well to treatment with fluocinonide ointment 0.05%. Nearly 2 years after the initial presentation, she developed recurrent symptoms and sought further treatment. She reported frequent scratching in association with episodes of anxiety. Examination revealed numerous 1- to 3-mm, flesh-colored to light brown, monomorphic, dome-shaped papules over the extensor surfaces of the bilateral arms and left pretibial surface (Figure 1).

^4-6

The possibility remains that this patient first presented with LSC 2 years prior and secondarily developed LA due to chronic trauma. Indeed, LA has been proposed as a variant of LSC. In both conditions, scratching seems to be the most important factor in the development of lesions. It has been proposed that treatment should primarily focus on the amelioration of pruritus.⁵

Five percent to 10% of cases of LA have been found to have some form of upper extremity involvement.⁷ However, these cases typically are associated with a generalized presentation involving the trunk and arms.^2,7 Our patient had no evidence of disease elsewhere. When evaluating a localized, pruritic, monomorphic, papular eruption on the extensor surfaces of the arms, LA may be an important consideration.

To the Editor:

Lichen amyloidosis (LA) classically presents as a pruritic, hyperkeratotic, papular eruption localized to the pretibial surface of the legs.¹ Nonpruritic and generalized variants have been reported but are rare.² Although it is the most common subtype of primary localized cutaneous amyloidosis, LA is a benign condition but is difficult to eradicate.¹ The precise pathophysiology is poorly understood, but chronic frictional irritation is closely associated with the eruption. We present a nongeneralized case of LA in an atypical location.

A healthy 30-year-old woman presented with an intermittent itchy rash on the elbows and knees of 2 years’ duration. The patient was first diagnosed with lichen simplex chronicus (LSC) and initially responded well to treatment with fluocinonide ointment 0.05%. Nearly 2 years after the initial presentation, she developed recurrent symptoms and sought further treatment. She reported frequent scratching in association with episodes of anxiety. Examination revealed numerous 1- to 3-mm, flesh-colored to light brown, monomorphic, dome-shaped papules over the extensor surfaces of the bilateral arms and left pretibial surface (Figure 1).

^4-6

The possibility remains that this patient first presented with LSC 2 years prior and secondarily developed LA due to chronic trauma. Indeed, LA has been proposed as a variant of LSC. In both conditions, scratching seems to be the most important factor in the development of lesions. It has been proposed that treatment should primarily focus on the amelioration of pruritus.⁵

Five percent to 10% of cases of LA have been found to have some form of upper extremity involvement.⁷ However, these cases typically are associated with a generalized presentation involving the trunk and arms.^2,7 Our patient had no evidence of disease elsewhere. When evaluating a localized, pruritic, monomorphic, papular eruption on the extensor surfaces of the arms, LA may be an important consideration.