Dermatopathology

Granular cell tumors (GCTs) tend to present as solitary nodules, not uncommonly affecting the dorsum of the tongue but also involving the skin, breasts, and internal organs.¹ Cutaneous GCTs typically present as 0.5- to 3-cm firm nodules with a verrucous or eroded surface.² They most commonly present in dark-skinned, middle-aged women but have been reported in all age groups and in both sexes.³ Multiple GCTs are reported in up to 25% of cases, rarely in association with LEOPARD syndrome (consisting of lentigines, electrocardiographic abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth, and deafness).⁴ Granular cell tumors generally are benign with a metastatic rate of approximately 3%.²

Granular cell tumors are histopathologically characterized by sheets of large polygonal cells with small, round, central nuclei; cytoplasm that is eosinophilic, coarse, and granular, as well as periodic acid–Schiff positive and diastase resistant; and distinct cytoplasmic membranes (Figure 1). Pustulo-ovoid bodies of Milian often generally appear as larger eosinophilic granules surrounded by a clear halo (Figure 2).⁵ Increased mitotic activity, a high nuclear-cytoplasmic ratio, pleomorphism, and necrosis suggest malignancy.⁶

Figure 1. Pseudoepitheliomatous hyperplasia and sheets of polygonal cells with light pink cytoplasm of a granular cell tumor (H&E, original magnification ×40).

Figure 2. Sheets of large polygonal cells with central nuclei; coarse, eosinophilic, granular cytoplasm; and large eosinophilic cytoplasmic pustulo-ovoid bodies of Milian characterize a granular cell tumor (H&E, original magnification ×600).

Lepromatous leprosy is characterized by sheets of histiocytes with vacuolated cytoplasm, some with clumped amphophilic bacilli known as globi (Figure 3). Mastocytoma can be distinguished from GCTs by the “fried egg” appearance of the mast cells (Figure 4). Although mast cells have a pale granular cytoplasm, they are smaller and lack pustulo-ovoid bodies and the polygonal shape of GCT cells. Reticulohistiocytoma, on the other hand, has two-toned dusty rose ground glass histiocytes (Figure 5), and xanthelasma can be distinguished histologically from GCT by the presence of a foamy rather than granular cytoplasm (Figure 6).

Figure 3. Lymphohistiocytic infiltrate with amphophilic collections of mycobacteria (globi) in lepromatous leprosy (H&E, original magnification ×600).

Figure 4. Small “fried egg” mast cells with pale granular cytoplasm and admixed eosinophils in a mastocytoma (H&E, original magnification ×600).

Figure 5. Sea of histiocytes containing dusty rose or ground glass cytoplasm with two-toned darker and lighter areas in a reticulohistiocytoma (H&E, original magnification ×600).

Figure 6. Aggregates of histiocytes with foamy cytoplasm in xanthelasma (H&E, original magnifi-cation ×600).

Granular cell tumors (GCTs) tend to present as solitary nodules, not uncommonly affecting the dorsum of the tongue but also involving the skin, breasts, and internal organs.¹ Cutaneous GCTs typically present as 0.5- to 3-cm firm nodules with a verrucous or eroded surface.² They most commonly present in dark-skinned, middle-aged women but have been reported in all age groups and in both sexes.³ Multiple GCTs are reported in up to 25% of cases, rarely in association with LEOPARD syndrome (consisting of lentigines, electrocardiographic abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth, and deafness).⁴ Granular cell tumors generally are benign with a metastatic rate of approximately 3%.²

Granular cell tumors are histopathologically characterized by sheets of large polygonal cells with small, round, central nuclei; cytoplasm that is eosinophilic, coarse, and granular, as well as periodic acid–Schiff positive and diastase resistant; and distinct cytoplasmic membranes (Figure 1). Pustulo-ovoid bodies of Milian often generally appear as larger eosinophilic granules surrounded by a clear halo (Figure 2).⁵ Increased mitotic activity, a high nuclear-cytoplasmic ratio, pleomorphism, and necrosis suggest malignancy.⁶

Figure 1. Pseudoepitheliomatous hyperplasia and sheets of polygonal cells with light pink cytoplasm of a granular cell tumor (H&E, original magnification ×40).

Figure 2. Sheets of large polygonal cells with central nuclei; coarse, eosinophilic, granular cytoplasm; and large eosinophilic cytoplasmic pustulo-ovoid bodies of Milian characterize a granular cell tumor (H&E, original magnification ×600).

Lepromatous leprosy is characterized by sheets of histiocytes with vacuolated cytoplasm, some with clumped amphophilic bacilli known as globi (Figure 3). Mastocytoma can be distinguished from GCTs by the “fried egg” appearance of the mast cells (Figure 4). Although mast cells have a pale granular cytoplasm, they are smaller and lack pustulo-ovoid bodies and the polygonal shape of GCT cells. Reticulohistiocytoma, on the other hand, has two-toned dusty rose ground glass histiocytes (Figure 5), and xanthelasma can be distinguished histologically from GCT by the presence of a foamy rather than granular cytoplasm (Figure 6).

Figure 3. Lymphohistiocytic infiltrate with amphophilic collections of mycobacteria (globi) in lepromatous leprosy (H&E, original magnification ×600).

Figure 4. Small “fried egg” mast cells with pale granular cytoplasm and admixed eosinophils in a mastocytoma (H&E, original magnification ×600).

Figure 5. Sea of histiocytes containing dusty rose or ground glass cytoplasm with two-toned darker and lighter areas in a reticulohistiocytoma (H&E, original magnification ×600).

Figure 6. Aggregates of histiocytes with foamy cytoplasm in xanthelasma (H&E, original magnifi-cation ×600).

Granular cell tumors (GCTs) tend to present as solitary nodules, not uncommonly affecting the dorsum of the tongue but also involving the skin, breasts, and internal organs.¹ Cutaneous GCTs typically present as 0.5- to 3-cm firm nodules with a verrucous or eroded surface.² They most commonly present in dark-skinned, middle-aged women but have been reported in all age groups and in both sexes.³ Multiple GCTs are reported in up to 25% of cases, rarely in association with LEOPARD syndrome (consisting of lentigines, electrocardiographic abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth, and deafness).⁴ Granular cell tumors generally are benign with a metastatic rate of approximately 3%.²

Granular cell tumors are histopathologically characterized by sheets of large polygonal cells with small, round, central nuclei; cytoplasm that is eosinophilic, coarse, and granular, as well as periodic acid–Schiff positive and diastase resistant; and distinct cytoplasmic membranes (Figure 1). Pustulo-ovoid bodies of Milian often generally appear as larger eosinophilic granules surrounded by a clear halo (Figure 2).⁵ Increased mitotic activity, a high nuclear-cytoplasmic ratio, pleomorphism, and necrosis suggest malignancy.⁶

Figure 1. Pseudoepitheliomatous hyperplasia and sheets of polygonal cells with light pink cytoplasm of a granular cell tumor (H&E, original magnification ×40).

Figure 2. Sheets of large polygonal cells with central nuclei; coarse, eosinophilic, granular cytoplasm; and large eosinophilic cytoplasmic pustulo-ovoid bodies of Milian characterize a granular cell tumor (H&E, original magnification ×600).

Lepromatous leprosy is characterized by sheets of histiocytes with vacuolated cytoplasm, some with clumped amphophilic bacilli known as globi (Figure 3). Mastocytoma can be distinguished from GCTs by the “fried egg” appearance of the mast cells (Figure 4). Although mast cells have a pale granular cytoplasm, they are smaller and lack pustulo-ovoid bodies and the polygonal shape of GCT cells. Reticulohistiocytoma, on the other hand, has two-toned dusty rose ground glass histiocytes (Figure 5), and xanthelasma can be distinguished histologically from GCT by the presence of a foamy rather than granular cytoplasm (Figure 6).

Figure 3. Lymphohistiocytic infiltrate with amphophilic collections of mycobacteria (globi) in lepromatous leprosy (H&E, original magnification ×600).

Figure 4. Small “fried egg” mast cells with pale granular cytoplasm and admixed eosinophils in a mastocytoma (H&E, original magnification ×600).

Figure 5. Sea of histiocytes containing dusty rose or ground glass cytoplasm with two-toned darker and lighter areas in a reticulohistiocytoma (H&E, original magnification ×600).

Figure 6. Aggregates of histiocytes with foamy cytoplasm in xanthelasma (H&E, original magnifi-cation ×600).

The Diagnosis: Tumor of the Follicular Infundibulum

Histopathologic findings from a facial papule in our patient revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (Figure). There was no atypia. Gomori methenamine-silver and periodic acid–Schiff stains for fungi were negative. The combined clinical presentation and histopathologic findings supported the diagnosis of multiple tumor of the follicular infundibulum (TFI).

Tumor of the follicular infundibulum was diagnosed based on a biopsy from the right cheek that revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (A and B)(H&E, original magnifications ×40 and ×100).

Tumor of the follicular infundibulum is an uncommon benign neoplasm that was first described in 1961 by Mehregan and Butler.¹ The reported frequency is 10 per 100,000 biopsies.² The majority of cases have been reported as solitary lesions, and multiple TFI are rare.³ Tumor of the follicular infundibulum affects middle-aged and elderly individuals with a female predominance.⁴ Multiple lesions generally range in number from 10 to 20, but there are few reports of more than 100 lesions.^2,3,5,6 The solitary tumors often are initially misdiagnosed as basal cell carcinomas (BCCs) or seborrheic keratosis. Multiple TFI have been described variably as hypopigmented, flesh-colored and pink, flat and slightly depressed macules and thin papules. Sites of predilection include the scalp, face, neck, and upper trunk.^2,3,5

There is no histopathologic difference between solitary and multiple TFI. Tumor of the follicular infundibulum displays a characteristic pale platelike proliferation of keratinocytes within the upper dermis attached to the overlying epidermis. The proliferating cells stain positive with periodic acid–Schiff, diastase-digestible glycogen is present in the cells at the base of the tumor, and a thickened network or brushlike pattern of elastic fibers surrounds the periphery of the tumor.¹ Tumor of the follicular infundibulum is occasionally discovered incidentally on biopsy and has been observed in the margin of wide excisions of a variety of neoplasms including BCC.⁷ Based on the close association of TFI and BCC in the same specimens, Weyers et al⁷ concluded that TFI may be a nonaggressive type of BCC. Cribier and Grosshans² reported 2 cases of TFI overlying a nevus sebaceous and a fibroma.

Treatment of TFI includes topical keratolytics, topical retinoic acid,⁵ imiquimod,⁸ topical steroids, and oral etretinate,⁶ all of which result in minimal improvement or incomplete resolution. Destructive treatments include cryotherapy, curettage, electrosurgery, laser ablation, and surgical excision, but all may lead to an unacceptable cosmetic result.

The Diagnosis: Tumor of the Follicular Infundibulum

Histopathologic findings from a facial papule in our patient revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (Figure). There was no atypia. Gomori methenamine-silver and periodic acid–Schiff stains for fungi were negative. The combined clinical presentation and histopathologic findings supported the diagnosis of multiple tumor of the follicular infundibulum (TFI).

Tumor of the follicular infundibulum was diagnosed based on a biopsy from the right cheek that revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (A and B)(H&E, original magnifications ×40 and ×100).

Tumor of the follicular infundibulum is an uncommon benign neoplasm that was first described in 1961 by Mehregan and Butler.¹ The reported frequency is 10 per 100,000 biopsies.² The majority of cases have been reported as solitary lesions, and multiple TFI are rare.³ Tumor of the follicular infundibulum affects middle-aged and elderly individuals with a female predominance.⁴ Multiple lesions generally range in number from 10 to 20, but there are few reports of more than 100 lesions.^2,3,5,6 The solitary tumors often are initially misdiagnosed as basal cell carcinomas (BCCs) or seborrheic keratosis. Multiple TFI have been described variably as hypopigmented, flesh-colored and pink, flat and slightly depressed macules and thin papules. Sites of predilection include the scalp, face, neck, and upper trunk.^2,3,5

There is no histopathologic difference between solitary and multiple TFI. Tumor of the follicular infundibulum displays a characteristic pale platelike proliferation of keratinocytes within the upper dermis attached to the overlying epidermis. The proliferating cells stain positive with periodic acid–Schiff, diastase-digestible glycogen is present in the cells at the base of the tumor, and a thickened network or brushlike pattern of elastic fibers surrounds the periphery of the tumor.¹ Tumor of the follicular infundibulum is occasionally discovered incidentally on biopsy and has been observed in the margin of wide excisions of a variety of neoplasms including BCC.⁷ Based on the close association of TFI and BCC in the same specimens, Weyers et al⁷ concluded that TFI may be a nonaggressive type of BCC. Cribier and Grosshans² reported 2 cases of TFI overlying a nevus sebaceous and a fibroma.

Treatment of TFI includes topical keratolytics, topical retinoic acid,⁵ imiquimod,⁸ topical steroids, and oral etretinate,⁶ all of which result in minimal improvement or incomplete resolution. Destructive treatments include cryotherapy, curettage, electrosurgery, laser ablation, and surgical excision, but all may lead to an unacceptable cosmetic result.

The Diagnosis: Tumor of the Follicular Infundibulum

Histopathologic findings from a facial papule in our patient revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (Figure). There was no atypia. Gomori methenamine-silver and periodic acid–Schiff stains for fungi were negative. The combined clinical presentation and histopathologic findings supported the diagnosis of multiple tumor of the follicular infundibulum (TFI).

Tumor of the follicular infundibulum was diagnosed based on a biopsy from the right cheek that revealed multifocal hyperplasia of anastomosing follicular infundibular cells with multiple connections to the overlying epidermis (A and B)(H&E, original magnifications ×40 and ×100).

Tumor of the follicular infundibulum is an uncommon benign neoplasm that was first described in 1961 by Mehregan and Butler.¹ The reported frequency is 10 per 100,000 biopsies.² The majority of cases have been reported as solitary lesions, and multiple TFI are rare.³ Tumor of the follicular infundibulum affects middle-aged and elderly individuals with a female predominance.⁴ Multiple lesions generally range in number from 10 to 20, but there are few reports of more than 100 lesions.^2,3,5,6 The solitary tumors often are initially misdiagnosed as basal cell carcinomas (BCCs) or seborrheic keratosis. Multiple TFI have been described variably as hypopigmented, flesh-colored and pink, flat and slightly depressed macules and thin papules. Sites of predilection include the scalp, face, neck, and upper trunk.^2,3,5

There is no histopathologic difference between solitary and multiple TFI. Tumor of the follicular infundibulum displays a characteristic pale platelike proliferation of keratinocytes within the upper dermis attached to the overlying epidermis. The proliferating cells stain positive with periodic acid–Schiff, diastase-digestible glycogen is present in the cells at the base of the tumor, and a thickened network or brushlike pattern of elastic fibers surrounds the periphery of the tumor.¹ Tumor of the follicular infundibulum is occasionally discovered incidentally on biopsy and has been observed in the margin of wide excisions of a variety of neoplasms including BCC.⁷ Based on the close association of TFI and BCC in the same specimens, Weyers et al⁷ concluded that TFI may be a nonaggressive type of BCC. Cribier and Grosshans² reported 2 cases of TFI overlying a nevus sebaceous and a fibroma.

Treatment of TFI includes topical keratolytics, topical retinoic acid,⁵ imiquimod,⁸ topical steroids, and oral etretinate,⁶ all of which result in minimal improvement or incomplete resolution. Destructive treatments include cryotherapy, curettage, electrosurgery, laser ablation, and surgical excision, but all may lead to an unacceptable cosmetic result.

Sulfur spring dermatitis is characterized by multiple punched-out erosions and pits. In prior case reports, patients often presented with painful swollen lesions that developed within 24 hours of bathing in hot sulfur springs.¹ Because spa therapy and thermal spring baths are common in modern society, dermatologists should be aware of sulfur spring dermatitis as a potential adverse effect.

Case Report

A healthy 65-year-old man presented with painful skin lesions on the legs that developed after bathing for 25 minutes in a hot sulfur spring 1 day prior. The patient had no history of dermatologic disease. He reported a 10-year history of bathing in a hot sulfur spring for 20 minutes every 3 days in the winter. This time, he bathed 5 minutes longer than usual. No skin condition was noted prior to bathing, but he reported feeling a tickling sensation and scratching the legs while he was immersed in the water. One hour after bathing, he noted confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (Figure 1).

Figure 1. Multiple confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (A and B).

Figure 2. The epidermis showed sharply demarcated, homogeneous necrosis (A)(H&E, original magni-fication ×40). Higher magnification demonstrated homogeneous coagulation necrosis of the epidermis, with many neutrophils present under the necrosis (B)(H&E, original magnification ×200).

A skin biopsy revealed sharply demarcated, homogeneous coagulation necrosis of the epidermis. Many neutrophils were present under the necrosis (Figure 2). Periodic acid–Schiff and acid-fast stains were negative for infectious organisms, and a skin tissue culture yielded negative results. Intensive wound care was started with nitrofurazone ointment 0.2%. The ulcers healed gradually in the following months with scar formation and hyperpigmentation.

Comment

Thermal sulfur baths are a form of balneotherapy promoted in many cultures for improvement of skin conditions; however, certain uncommon skin problems may occur after bathing in hot sulfur springs.² In particular, sulfur spring dermatitis is a potential adverse effect.

Thermal sulfur water is known to exert anti-inflammatory, keratoplastic, and antipruriginous effects. As a result, it often is used in many cultures as an alternative treatment of various skin conditions.^2-4 Moreover, thermal sulfur baths are popular in northeastern Asian countries for their effects on mental health.⁵ Hot springs in northern Taiwan, which contain large amounts of hydrogen sulfide, sulfate, and sulfur differ from other thermal springs in that they are rather acidic in nature and release geothermal energy from volcanic activity.⁶ In addition to hot sulfur springs, there are neutral salt and CO₂ springs in Taiwan.⁵ However, spring dermatitis has only been associated with bathing in hot sulfur springs due to high concentrations of hydrogen sulfide that break down keratin and cause dissolution of the stratum corneum.⁷

The incidence of sulfur spring dermatitis is unknown. Although the largest known case series reported 44 cases occurring within a decade in Taiwan,¹ it is rarely seen in our daily practice. Previously reported cases of sulfur spring dermatitis noted clinical findings of swelling of the affected area followed by punched-out erosions with surrounding erythema. Most lesions gradually healed with dry brownish crusts. A patch test with sulfur spring water and sulfur compounds showed negative results; therefore, the mechanism is unlikely to be allergic reaction.¹ The clinical differential diagnosis includes factitious ulcers as well as viral and fungal infections. A tissue culture should be performed to exclude infectious conditions.

This characteristic skin disease does not present in all individuals after bathing in hot sulfur springs. Lesions may present anywhere on the body with a predilection for skin folds, including the penis and scrotum. Preexisting skin conditions such as pruritus and xerosis are considered to be contributing factors. The possible etiology of sulfur spring dermatitis may be acid irritation from the unstable amount of soluble sulfur in the water, which is enhanced by the heat.¹ In our patient, no prior skin disease was noted, but he scratched the skin on the thighs while bathing, which may have contributed to the development of lesions in this area rather than in the skin folds.

The skin biopsy specimen demonstrated epidermal coagulation necrosis, mild superficial dermal damage, and preservation of the pilosebaceous appendages. The ulcers were painful during healing and resolved with scarring and hyperpigmentation. The histopathologic findings and clinical course in our patient were similar to cases of superficial second-degree burns.⁸ It is possible that the keratoplastic effect of sulfur at high concentrations along with thermal water caused the skin condition.

Conclusion

Individuals who engage in thermal sulfur baths should be aware of potential adverse effects such as sulfur spring dermatitis, especially those with preexisting skin disorders.

Sulfur spring dermatitis is characterized by multiple punched-out erosions and pits. In prior case reports, patients often presented with painful swollen lesions that developed within 24 hours of bathing in hot sulfur springs.¹ Because spa therapy and thermal spring baths are common in modern society, dermatologists should be aware of sulfur spring dermatitis as a potential adverse effect.

Case Report

A healthy 65-year-old man presented with painful skin lesions on the legs that developed after bathing for 25 minutes in a hot sulfur spring 1 day prior. The patient had no history of dermatologic disease. He reported a 10-year history of bathing in a hot sulfur spring for 20 minutes every 3 days in the winter. This time, he bathed 5 minutes longer than usual. No skin condition was noted prior to bathing, but he reported feeling a tickling sensation and scratching the legs while he was immersed in the water. One hour after bathing, he noted confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (Figure 1).

Figure 1. Multiple confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (A and B).

Figure 2. The epidermis showed sharply demarcated, homogeneous necrosis (A)(H&E, original magni-fication ×40). Higher magnification demonstrated homogeneous coagulation necrosis of the epidermis, with many neutrophils present under the necrosis (B)(H&E, original magnification ×200).

A skin biopsy revealed sharply demarcated, homogeneous coagulation necrosis of the epidermis. Many neutrophils were present under the necrosis (Figure 2). Periodic acid–Schiff and acid-fast stains were negative for infectious organisms, and a skin tissue culture yielded negative results. Intensive wound care was started with nitrofurazone ointment 0.2%. The ulcers healed gradually in the following months with scar formation and hyperpigmentation.

Comment

Thermal sulfur baths are a form of balneotherapy promoted in many cultures for improvement of skin conditions; however, certain uncommon skin problems may occur after bathing in hot sulfur springs.² In particular, sulfur spring dermatitis is a potential adverse effect.

Thermal sulfur water is known to exert anti-inflammatory, keratoplastic, and antipruriginous effects. As a result, it often is used in many cultures as an alternative treatment of various skin conditions.^2-4 Moreover, thermal sulfur baths are popular in northeastern Asian countries for their effects on mental health.⁵ Hot springs in northern Taiwan, which contain large amounts of hydrogen sulfide, sulfate, and sulfur differ from other thermal springs in that they are rather acidic in nature and release geothermal energy from volcanic activity.⁶ In addition to hot sulfur springs, there are neutral salt and CO₂ springs in Taiwan.⁵ However, spring dermatitis has only been associated with bathing in hot sulfur springs due to high concentrations of hydrogen sulfide that break down keratin and cause dissolution of the stratum corneum.⁷

The incidence of sulfur spring dermatitis is unknown. Although the largest known case series reported 44 cases occurring within a decade in Taiwan,¹ it is rarely seen in our daily practice. Previously reported cases of sulfur spring dermatitis noted clinical findings of swelling of the affected area followed by punched-out erosions with surrounding erythema. Most lesions gradually healed with dry brownish crusts. A patch test with sulfur spring water and sulfur compounds showed negative results; therefore, the mechanism is unlikely to be allergic reaction.¹ The clinical differential diagnosis includes factitious ulcers as well as viral and fungal infections. A tissue culture should be performed to exclude infectious conditions.

This characteristic skin disease does not present in all individuals after bathing in hot sulfur springs. Lesions may present anywhere on the body with a predilection for skin folds, including the penis and scrotum. Preexisting skin conditions such as pruritus and xerosis are considered to be contributing factors. The possible etiology of sulfur spring dermatitis may be acid irritation from the unstable amount of soluble sulfur in the water, which is enhanced by the heat.¹ In our patient, no prior skin disease was noted, but he scratched the skin on the thighs while bathing, which may have contributed to the development of lesions in this area rather than in the skin folds.

The skin biopsy specimen demonstrated epidermal coagulation necrosis, mild superficial dermal damage, and preservation of the pilosebaceous appendages. The ulcers were painful during healing and resolved with scarring and hyperpigmentation. The histopathologic findings and clinical course in our patient were similar to cases of superficial second-degree burns.⁸ It is possible that the keratoplastic effect of sulfur at high concentrations along with thermal water caused the skin condition.

Conclusion

Individuals who engage in thermal sulfur baths should be aware of potential adverse effects such as sulfur spring dermatitis, especially those with preexisting skin disorders.

Sulfur spring dermatitis is characterized by multiple punched-out erosions and pits. In prior case reports, patients often presented with painful swollen lesions that developed within 24 hours of bathing in hot sulfur springs.¹ Because spa therapy and thermal spring baths are common in modern society, dermatologists should be aware of sulfur spring dermatitis as a potential adverse effect.

Case Report

A healthy 65-year-old man presented with painful skin lesions on the legs that developed after bathing for 25 minutes in a hot sulfur spring 1 day prior. The patient had no history of dermatologic disease. He reported a 10-year history of bathing in a hot sulfur spring for 20 minutes every 3 days in the winter. This time, he bathed 5 minutes longer than usual. No skin condition was noted prior to bathing, but he reported feeling a tickling sensation and scratching the legs while he was immersed in the water. One hour after bathing, he noted confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (Figure 1).

Figure 1. Multiple confluent, punched-out, round ulcers with peripheral erythema on the thighs and shins (A and B).

Figure 2. The epidermis showed sharply demarcated, homogeneous necrosis (A)(H&E, original magni-fication ×40). Higher magnification demonstrated homogeneous coagulation necrosis of the epidermis, with many neutrophils present under the necrosis (B)(H&E, original magnification ×200).

A skin biopsy revealed sharply demarcated, homogeneous coagulation necrosis of the epidermis. Many neutrophils were present under the necrosis (Figure 2). Periodic acid–Schiff and acid-fast stains were negative for infectious organisms, and a skin tissue culture yielded negative results. Intensive wound care was started with nitrofurazone ointment 0.2%. The ulcers healed gradually in the following months with scar formation and hyperpigmentation.

Comment

Thermal sulfur baths are a form of balneotherapy promoted in many cultures for improvement of skin conditions; however, certain uncommon skin problems may occur after bathing in hot sulfur springs.² In particular, sulfur spring dermatitis is a potential adverse effect.

Thermal sulfur water is known to exert anti-inflammatory, keratoplastic, and antipruriginous effects. As a result, it often is used in many cultures as an alternative treatment of various skin conditions.^2-4 Moreover, thermal sulfur baths are popular in northeastern Asian countries for their effects on mental health.⁵ Hot springs in northern Taiwan, which contain large amounts of hydrogen sulfide, sulfate, and sulfur differ from other thermal springs in that they are rather acidic in nature and release geothermal energy from volcanic activity.⁶ In addition to hot sulfur springs, there are neutral salt and CO₂ springs in Taiwan.⁵ However, spring dermatitis has only been associated with bathing in hot sulfur springs due to high concentrations of hydrogen sulfide that break down keratin and cause dissolution of the stratum corneum.⁷

The incidence of sulfur spring dermatitis is unknown. Although the largest known case series reported 44 cases occurring within a decade in Taiwan,¹ it is rarely seen in our daily practice. Previously reported cases of sulfur spring dermatitis noted clinical findings of swelling of the affected area followed by punched-out erosions with surrounding erythema. Most lesions gradually healed with dry brownish crusts. A patch test with sulfur spring water and sulfur compounds showed negative results; therefore, the mechanism is unlikely to be allergic reaction.¹ The clinical differential diagnosis includes factitious ulcers as well as viral and fungal infections. A tissue culture should be performed to exclude infectious conditions.

This characteristic skin disease does not present in all individuals after bathing in hot sulfur springs. Lesions may present anywhere on the body with a predilection for skin folds, including the penis and scrotum. Preexisting skin conditions such as pruritus and xerosis are considered to be contributing factors. The possible etiology of sulfur spring dermatitis may be acid irritation from the unstable amount of soluble sulfur in the water, which is enhanced by the heat.¹ In our patient, no prior skin disease was noted, but he scratched the skin on the thighs while bathing, which may have contributed to the development of lesions in this area rather than in the skin folds.

The skin biopsy specimen demonstrated epidermal coagulation necrosis, mild superficial dermal damage, and preservation of the pilosebaceous appendages. The ulcers were painful during healing and resolved with scarring and hyperpigmentation. The histopathologic findings and clinical course in our patient were similar to cases of superficial second-degree burns.⁸ It is possible that the keratoplastic effect of sulfur at high concentrations along with thermal water caused the skin condition.

Conclusion

Individuals who engage in thermal sulfur baths should be aware of potential adverse effects such as sulfur spring dermatitis, especially those with preexisting skin disorders.

A fibrous papule is a common benign lesion that usually presents in adults on the face,  especially on the lower portion of the nose. It typically presents as a small (2–5 mm), asymptomatic, flesh-colored, dome-shaped lesion that is firm and nontender. Several histopathologic variants of fibrous papules have been described, including clear cell, granular, epithelioid, hypercellular, pleomorphic, pigmented, and inflammatory.¹ Clear cell fibrous papules are exceedingly rare. On microscopic examination the epidermis may be normal or show some degree of hyperkeratosis and parakeratosis, erosion, ulceration, or crust. The basal layer may show an increase of melanin. The dermis is expanded by a proliferation of clear cells arranged in sheets, clusters, or as single cells (Figure 1). The clear cells show variation in size and shape. The nuclei are small and round without pleomorphism, hyperchromasia, or mitoses. The nuclei may be centrally located or eccentrically displaced by a large intracytoplasmic vacuole (Figure 2). Some clear cells may exhibit finely vacuolated cytoplasm with nuclear scalloping. The surrounding stroma usually consists of sclerotic collagen and dilated blood vessels (Figure 3). Extravasated red blood cells may be present focally. Patchy lymphocytic infiltrates may be found in the stroma at the periphery of the lesion. Periodic acid–Schiff and mucicarmine staining of the clear cells is negative. On immunohistochemistry, the clear cells are diffusely positive for vimentin and negative for cytokeratin AE1/AE3, epithelial membrane antigen, carcinoembryonic antigen, and HMB-45 (human melanoma black 45).^2,3 The clear cells often are positive for CD68, factor XIIIa, and NKI/C3 (anti-CD63) but also may be negative. The S-100 protein often is negative but may be focally positive.

The differential diagnosis for clear cell fibrous papules is broad but reasonably includes balloon cell nevus, clear cell hidradenoma, and cutaneous metastasis of clear cell (conventional) renal cell carcinoma (ccRCC). Balloon cell malignant melanoma is not considered strongly in the differential diagnosis because it usually exhibits invasive growth, cytologic atypia, and mitoses, all of which are not characteristic morphologic features of clear cell fibrous papules.

A balloon cell nevus may be difficult to distinguish from a clear cell fibrous papule on routine hematoxylin and eosin staining (Figure 4); however, the nuclei of a balloon cell nevus tend to be more rounded and centrally located. Any junctional nesting or nests of conventional nevus cells in the dermis also help differentiate a balloon cell nevus from a clear cell fibrous papule. Diffusely positive immunostaining for S-100 protein also is indicative of a balloon cell nevus.

Clear cell hidradenoma consists predominantly of cells with clear cytoplasm and small dark nuclei that may closely mimic a clear cell fibrous papule (Figure 5) but often shows a second population of cells with more vesicular nuclei and dark eosinophilic cytoplasm. Cystic spaces containing hyaline material and foci of squamoid change are common, along with occasional tubular lumina that may be prominent or inconspicuous. Further, the tumor cells of clear cell hidradenoma show positive immunostaining for epithelial markers (eg, cytokeratin AE1/AE3, CAM5.2).

Cutaneous metastasis of ccRCC is rare and usually presents clinically as a larger lesion than a clear cell fibrous papule. The cells of ccRCC have moderate to abundant clear cytoplasm and nuclei with varying degrees of pleomorphism (Figure 6). Periodic acid–Schiff staining demonstrates intracytoplasmic glycogen. The stroma is abundantly vascular and extravasated blood cells are frequently observed. On immunohistochemistry, the tumor cells of ccRCC stain positively for cytokeratin AE1/AE3, CAM5.2, epithelial membrane antigen, CD10, and vimentin.

A fibrous papule is a common benign lesion that usually presents in adults on the face,  especially on the lower portion of the nose. It typically presents as a small (2–5 mm), asymptomatic, flesh-colored, dome-shaped lesion that is firm and nontender. Several histopathologic variants of fibrous papules have been described, including clear cell, granular, epithelioid, hypercellular, pleomorphic, pigmented, and inflammatory.¹ Clear cell fibrous papules are exceedingly rare. On microscopic examination the epidermis may be normal or show some degree of hyperkeratosis and parakeratosis, erosion, ulceration, or crust. The basal layer may show an increase of melanin. The dermis is expanded by a proliferation of clear cells arranged in sheets, clusters, or as single cells (Figure 1). The clear cells show variation in size and shape. The nuclei are small and round without pleomorphism, hyperchromasia, or mitoses. The nuclei may be centrally located or eccentrically displaced by a large intracytoplasmic vacuole (Figure 2). Some clear cells may exhibit finely vacuolated cytoplasm with nuclear scalloping. The surrounding stroma usually consists of sclerotic collagen and dilated blood vessels (Figure 3). Extravasated red blood cells may be present focally. Patchy lymphocytic infiltrates may be found in the stroma at the periphery of the lesion. Periodic acid–Schiff and mucicarmine staining of the clear cells is negative. On immunohistochemistry, the clear cells are diffusely positive for vimentin and negative for cytokeratin AE1/AE3, epithelial membrane antigen, carcinoembryonic antigen, and HMB-45 (human melanoma black 45).^2,3 The clear cells often are positive for CD68, factor XIIIa, and NKI/C3 (anti-CD63) but also may be negative. The S-100 protein often is negative but may be focally positive.

The differential diagnosis for clear cell fibrous papules is broad but reasonably includes balloon cell nevus, clear cell hidradenoma, and cutaneous metastasis of clear cell (conventional) renal cell carcinoma (ccRCC). Balloon cell malignant melanoma is not considered strongly in the differential diagnosis because it usually exhibits invasive growth, cytologic atypia, and mitoses, all of which are not characteristic morphologic features of clear cell fibrous papules.

A balloon cell nevus may be difficult to distinguish from a clear cell fibrous papule on routine hematoxylin and eosin staining (Figure 4); however, the nuclei of a balloon cell nevus tend to be more rounded and centrally located. Any junctional nesting or nests of conventional nevus cells in the dermis also help differentiate a balloon cell nevus from a clear cell fibrous papule. Diffusely positive immunostaining for S-100 protein also is indicative of a balloon cell nevus.

Clear cell hidradenoma consists predominantly of cells with clear cytoplasm and small dark nuclei that may closely mimic a clear cell fibrous papule (Figure 5) but often shows a second population of cells with more vesicular nuclei and dark eosinophilic cytoplasm. Cystic spaces containing hyaline material and foci of squamoid change are common, along with occasional tubular lumina that may be prominent or inconspicuous. Further, the tumor cells of clear cell hidradenoma show positive immunostaining for epithelial markers (eg, cytokeratin AE1/AE3, CAM5.2).

Cutaneous metastasis of ccRCC is rare and usually presents clinically as a larger lesion than a clear cell fibrous papule. The cells of ccRCC have moderate to abundant clear cytoplasm and nuclei with varying degrees of pleomorphism (Figure 6). Periodic acid–Schiff staining demonstrates intracytoplasmic glycogen. The stroma is abundantly vascular and extravasated blood cells are frequently observed. On immunohistochemistry, the tumor cells of ccRCC stain positively for cytokeratin AE1/AE3, CAM5.2, epithelial membrane antigen, CD10, and vimentin.

A fibrous papule is a common benign lesion that usually presents in adults on the face,  especially on the lower portion of the nose. It typically presents as a small (2–5 mm), asymptomatic, flesh-colored, dome-shaped lesion that is firm and nontender. Several histopathologic variants of fibrous papules have been described, including clear cell, granular, epithelioid, hypercellular, pleomorphic, pigmented, and inflammatory.¹ Clear cell fibrous papules are exceedingly rare. On microscopic examination the epidermis may be normal or show some degree of hyperkeratosis and parakeratosis, erosion, ulceration, or crust. The basal layer may show an increase of melanin. The dermis is expanded by a proliferation of clear cells arranged in sheets, clusters, or as single cells (Figure 1). The clear cells show variation in size and shape. The nuclei are small and round without pleomorphism, hyperchromasia, or mitoses. The nuclei may be centrally located or eccentrically displaced by a large intracytoplasmic vacuole (Figure 2). Some clear cells may exhibit finely vacuolated cytoplasm with nuclear scalloping. The surrounding stroma usually consists of sclerotic collagen and dilated blood vessels (Figure 3). Extravasated red blood cells may be present focally. Patchy lymphocytic infiltrates may be found in the stroma at the periphery of the lesion. Periodic acid–Schiff and mucicarmine staining of the clear cells is negative. On immunohistochemistry, the clear cells are diffusely positive for vimentin and negative for cytokeratin AE1/AE3, epithelial membrane antigen, carcinoembryonic antigen, and HMB-45 (human melanoma black 45).^2,3 The clear cells often are positive for CD68, factor XIIIa, and NKI/C3 (anti-CD63) but also may be negative. The S-100 protein often is negative but may be focally positive.

The differential diagnosis for clear cell fibrous papules is broad but reasonably includes balloon cell nevus, clear cell hidradenoma, and cutaneous metastasis of clear cell (conventional) renal cell carcinoma (ccRCC). Balloon cell malignant melanoma is not considered strongly in the differential diagnosis because it usually exhibits invasive growth, cytologic atypia, and mitoses, all of which are not characteristic morphologic features of clear cell fibrous papules.

A balloon cell nevus may be difficult to distinguish from a clear cell fibrous papule on routine hematoxylin and eosin staining (Figure 4); however, the nuclei of a balloon cell nevus tend to be more rounded and centrally located. Any junctional nesting or nests of conventional nevus cells in the dermis also help differentiate a balloon cell nevus from a clear cell fibrous papule. Diffusely positive immunostaining for S-100 protein also is indicative of a balloon cell nevus.

Clear cell hidradenoma consists predominantly of cells with clear cytoplasm and small dark nuclei that may closely mimic a clear cell fibrous papule (Figure 5) but often shows a second population of cells with more vesicular nuclei and dark eosinophilic cytoplasm. Cystic spaces containing hyaline material and foci of squamoid change are common, along with occasional tubular lumina that may be prominent or inconspicuous. Further, the tumor cells of clear cell hidradenoma show positive immunostaining for epithelial markers (eg, cytokeratin AE1/AE3, CAM5.2).

Cutaneous metastasis of ccRCC is rare and usually presents clinically as a larger lesion than a clear cell fibrous papule. The cells of ccRCC have moderate to abundant clear cytoplasm and nuclei with varying degrees of pleomorphism (Figure 6). Periodic acid–Schiff staining demonstrates intracytoplasmic glycogen. The stroma is abundantly vascular and extravasated blood cells are frequently observed. On immunohistochemistry, the tumor cells of ccRCC stain positively for cytokeratin AE1/AE3, CAM5.2, epithelial membrane antigen, CD10, and vimentin.

Lipidized dermatofibromas most commonly are found on the ankles, which has led some authors to refer to these lesions as ankle-type fibrous histiocytomas.¹ Compared to ordinary dermatofibromas, patients with lipidized dermatofibromas tend to be older, most commonly presenting in the fifth or sixth decades of life, and are predominantly male. Lipidized dermatofibromas typically present as well-circumscribed solitary nodules in the dermis. Characteristic features include numerous xanthomatous cells dissected by distinctive hyalinized wiry collagen fibers (Figures 1 and 2).¹ Xanthomatous cells can be round, polygonal, or stellate in shape. These characteristic features in combination with others of dermatofibromas (eg, epidermal acanthosis [Figure 1]) fulfill the criteria for diagnosis of a lipidized dermatofibroma. Additionally, lipidized dermatofibromas tend to be larger than ordinary dermatofibromas, which typically are less than 2 cm in diameter.¹

Figure 1. Lipidized dermatofibromas are characterized by classic epidermal features of dermatofibromas, such as acanthosis, along with numerous foam cells and extensive stromal hyalinization (H&E, original magnification ×1.5).

Figure 2. Higher-power view of a lipidized dermatofibroma shows the characteristic irregular dissection of hyalinized wiry collagen fibers between the xanthomatous cells (H&E, original magnification ×20).

Eruptive xanthomas are characterized by a lacelike infiltrate of extravascular lipid deposits between collagen bundles (Figure 3).² Granular cell tumors are composed of sheets and/or nests of large cells with abundant eosinophilic cytoplasm and may be confused with lipidized dermatofibromas, as they also may induce overlying pseudoepitheliomatous hyperplasia³; however, on closer examination of the cells, the cytoplasm is found to be granular (Figure 4), which contrasts the finely vacuolated cytoplasm of xanthomatous cells found in lipidized dermatofibromas. Giant lysosomal granules (eg, pustulo-ovoid bodies of Milian) are present in some cases.² Of note, an unusual variant of dermatofibroma exists that features prominent granular cells.⁴

Figure 3. Lacelike deposition of extravascular lipid deposits is seen infiltrating between collagen bundles in an eruptive xanthoma (H&E, original magnification ×20).

Figure 4. An abundant eosinophilic, finely granular cytoplasm is characteristic of granular cell tumor (H&E, original magnification ×40).

Tuberous xanthomas most commonly occur around the pressure areas, such as the knees, elbows, and buttocks. Foam cells are a main feature of tuberous xanthomas and are arranged in large aggregates throughout the dermis.² Tuberous xanthomas lack Touton giant cells or inflammatory cells. Older lesions tend to develop substantial fibrosis (Figure 5). Although foam cells can be present in older lesions, they are never as conspicuous as those found in other xanthomas.

Xanthogranulomas commonly occur on the head and neck. Findings noted on low magnification include a well-circumscribed exophytic nodule and an epidermal collarette, which help to easily distinguish xanthogranulomas from lipidized dermatofibromas. Additionally, the presence of a more prominent inflammatory infiltrate, which often includes eosinophils, as well as multinucleated Touton giant cells (Figure 6) and histiocytes with more eosinophilic and less xanthomatous cytoplasm can help distinguish between the lesions.^1,5 Notably, Touton giant cells also can be seen in lipidized dermatofibromas,¹ but the presence of unique features such as distinctive stromal hyalinization are clues to the correct diagnosis of a lipidized dermatofibroma.

Lipidized dermatofibromas most commonly are found on the ankles, which has led some authors to refer to these lesions as ankle-type fibrous histiocytomas.¹ Compared to ordinary dermatofibromas, patients with lipidized dermatofibromas tend to be older, most commonly presenting in the fifth or sixth decades of life, and are predominantly male. Lipidized dermatofibromas typically present as well-circumscribed solitary nodules in the dermis. Characteristic features include numerous xanthomatous cells dissected by distinctive hyalinized wiry collagen fibers (Figures 1 and 2).¹ Xanthomatous cells can be round, polygonal, or stellate in shape. These characteristic features in combination with others of dermatofibromas (eg, epidermal acanthosis [Figure 1]) fulfill the criteria for diagnosis of a lipidized dermatofibroma. Additionally, lipidized dermatofibromas tend to be larger than ordinary dermatofibromas, which typically are less than 2 cm in diameter.¹

Figure 1. Lipidized dermatofibromas are characterized by classic epidermal features of dermatofibromas, such as acanthosis, along with numerous foam cells and extensive stromal hyalinization (H&E, original magnification ×1.5).

Figure 2. Higher-power view of a lipidized dermatofibroma shows the characteristic irregular dissection of hyalinized wiry collagen fibers between the xanthomatous cells (H&E, original magnification ×20).

Eruptive xanthomas are characterized by a lacelike infiltrate of extravascular lipid deposits between collagen bundles (Figure 3).² Granular cell tumors are composed of sheets and/or nests of large cells with abundant eosinophilic cytoplasm and may be confused with lipidized dermatofibromas, as they also may induce overlying pseudoepitheliomatous hyperplasia³; however, on closer examination of the cells, the cytoplasm is found to be granular (Figure 4), which contrasts the finely vacuolated cytoplasm of xanthomatous cells found in lipidized dermatofibromas. Giant lysosomal granules (eg, pustulo-ovoid bodies of Milian) are present in some cases.² Of note, an unusual variant of dermatofibroma exists that features prominent granular cells.⁴

Figure 3. Lacelike deposition of extravascular lipid deposits is seen infiltrating between collagen bundles in an eruptive xanthoma (H&E, original magnification ×20).

Figure 4. An abundant eosinophilic, finely granular cytoplasm is characteristic of granular cell tumor (H&E, original magnification ×40).

Tuberous xanthomas most commonly occur around the pressure areas, such as the knees, elbows, and buttocks. Foam cells are a main feature of tuberous xanthomas and are arranged in large aggregates throughout the dermis.² Tuberous xanthomas lack Touton giant cells or inflammatory cells. Older lesions tend to develop substantial fibrosis (Figure 5). Although foam cells can be present in older lesions, they are never as conspicuous as those found in other xanthomas.

Xanthogranulomas commonly occur on the head and neck. Findings noted on low magnification include a well-circumscribed exophytic nodule and an epidermal collarette, which help to easily distinguish xanthogranulomas from lipidized dermatofibromas. Additionally, the presence of a more prominent inflammatory infiltrate, which often includes eosinophils, as well as multinucleated Touton giant cells (Figure 6) and histiocytes with more eosinophilic and less xanthomatous cytoplasm can help distinguish between the lesions.^1,5 Notably, Touton giant cells also can be seen in lipidized dermatofibromas,¹ but the presence of unique features such as distinctive stromal hyalinization are clues to the correct diagnosis of a lipidized dermatofibroma.

Lipidized dermatofibromas most commonly are found on the ankles, which has led some authors to refer to these lesions as ankle-type fibrous histiocytomas.¹ Compared to ordinary dermatofibromas, patients with lipidized dermatofibromas tend to be older, most commonly presenting in the fifth or sixth decades of life, and are predominantly male. Lipidized dermatofibromas typically present as well-circumscribed solitary nodules in the dermis. Characteristic features include numerous xanthomatous cells dissected by distinctive hyalinized wiry collagen fibers (Figures 1 and 2).¹ Xanthomatous cells can be round, polygonal, or stellate in shape. These characteristic features in combination with others of dermatofibromas (eg, epidermal acanthosis [Figure 1]) fulfill the criteria for diagnosis of a lipidized dermatofibroma. Additionally, lipidized dermatofibromas tend to be larger than ordinary dermatofibromas, which typically are less than 2 cm in diameter.¹

Figure 1. Lipidized dermatofibromas are characterized by classic epidermal features of dermatofibromas, such as acanthosis, along with numerous foam cells and extensive stromal hyalinization (H&E, original magnification ×1.5).

Figure 2. Higher-power view of a lipidized dermatofibroma shows the characteristic irregular dissection of hyalinized wiry collagen fibers between the xanthomatous cells (H&E, original magnification ×20).

Eruptive xanthomas are characterized by a lacelike infiltrate of extravascular lipid deposits between collagen bundles (Figure 3).² Granular cell tumors are composed of sheets and/or nests of large cells with abundant eosinophilic cytoplasm and may be confused with lipidized dermatofibromas, as they also may induce overlying pseudoepitheliomatous hyperplasia³; however, on closer examination of the cells, the cytoplasm is found to be granular (Figure 4), which contrasts the finely vacuolated cytoplasm of xanthomatous cells found in lipidized dermatofibromas. Giant lysosomal granules (eg, pustulo-ovoid bodies of Milian) are present in some cases.² Of note, an unusual variant of dermatofibroma exists that features prominent granular cells.⁴

Figure 3. Lacelike deposition of extravascular lipid deposits is seen infiltrating between collagen bundles in an eruptive xanthoma (H&E, original magnification ×20).

Figure 4. An abundant eosinophilic, finely granular cytoplasm is characteristic of granular cell tumor (H&E, original magnification ×40).

Tuberous xanthomas most commonly occur around the pressure areas, such as the knees, elbows, and buttocks. Foam cells are a main feature of tuberous xanthomas and are arranged in large aggregates throughout the dermis.² Tuberous xanthomas lack Touton giant cells or inflammatory cells. Older lesions tend to develop substantial fibrosis (Figure 5). Although foam cells can be present in older lesions, they are never as conspicuous as those found in other xanthomas.

Xanthogranulomas commonly occur on the head and neck. Findings noted on low magnification include a well-circumscribed exophytic nodule and an epidermal collarette, which help to easily distinguish xanthogranulomas from lipidized dermatofibromas. Additionally, the presence of a more prominent inflammatory infiltrate, which often includes eosinophils, as well as multinucleated Touton giant cells (Figure 6) and histiocytes with more eosinophilic and less xanthomatous cytoplasm can help distinguish between the lesions.^1,5 Notably, Touton giant cells also can be seen in lipidized dermatofibromas,¹ but the presence of unique features such as distinctive stromal hyalinization are clues to the correct diagnosis of a lipidized dermatofibroma.

Pigmented purpuric dermatoses (PPDs) are a group of common chronic disorders characterized by speckled, cayenne pepper–like petechiae and orange-brown discoloration of the skin resulting from capillaritis.¹ Pigmented purpuric dermatoses typically occur in the absence of underlying vascular insufficiency or other hematologic dysfunction. The 5 well-known clinicopathologic variants of PPD include Schamberg disease; purpura annularis telangiectodes of Majocchi; pigmented purpuric lichenoid dermatitis of Gougerot and Blum; eczematoidlike purpura of Doucas and Kapetanakis; and lichen aureus.² All PPDs share common characteristic clinical and histologic features. Clinically, patients generally present with symmetric petechiae and/or pigmented macules. All 5 PPD variants share similar histologic findings, including a vasculocentric lymphocytic infiltrate in the papillary dermis, swelling of the endothelial cells, erythrocyte extravasation, and often hemosiderin-laden macrophages.¹ Despite these clinical and histopathologic similarities, each variant contains additional distinctive features, such as telangiectasia (purpura annularis telangiectodes of Majocchi), a lichenoid infiltrate (pigmented purpuric lichenoid dermatitis of Gougerot and Blum), eczematous changes (eczematoidlike purpura of Doucas and Kapetanakis), and marked hemosiderin deposition (lichen aureus).

Granulomatous pigmented purpuric dermatosis (GPPD) is a rare variant of PPD.^3-7 Clinically, these lesions appear similar to other PPDs; however, in addition to the characteristic changes associated with conventional PPD, histologic examination of GPPD reveals a granulomatous inflammatory reaction pattern. Although the pathogenesis of GPPD is not well understood, its association with hyperlipidemia may suggest a granulomatous response to capillaritis mediated by lipid deposition in the microvasculature.^6,7

We present 3 cases of GPPD and provide a review of the literature. In all of our patients, biopsy specimens were fixed in 10% buffered formalin and embedded in paraffin by standard methodologies, and all stains were performed on sections by standard methodologies. Based on a PubMed search of articles indexed for MEDLINE using the terms granulomatous pigmented purpuric dermatosis, sarcoidosis, pigmented purpuric dermatosis, granulomas, and pigmented purpuric dermatosis, we review 5 additional reports describing 10 total patients.^3-7

Case Reports

Patient 1

A 9-year-old white boy presented with a 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (Figure, A). The lesion appeared 3 to 4 years prior to presentation but had become progressively darker and centrally indurated over the last 2 years. The patient and his mother denied any history of trauma to the area. His medical history was unremarkable, and his current medications included fish oil and multivitamin tablets.

Histologic examination of a punch biopsy specimen taken from the center of the lesion revealed a lichenoid lymphohistiocytic infiltrate with marked red blood cell (RBC) extravasation and associated hemosiderin-laden macrophages. The lymphocytes comprising this infiltrate lacked cytologic atypia and exhibited minimal epidermotropism (Figure, B). Additionally, there was a superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised ofepithelioid histiocytes in the mid and deep dermis (Figure, C). Periodic acid–Schiff, acid-fast bacilli (AFB), and Fite stains were negative for organisms. Polarization was negative for refractile foreign material. Due to the patient’s age, no treatment was performed, and the lesion remains unchanged 1 year after biopsy.

Patient 2

A 49-year-old white woman presented with a 2-cm yellow-brown patch with a faint, nonblanchable, violaceous center on the right lateral thigh of 4 months’ duration. The patch initially appeared as a small asymptomatic purple papule. The patient denied any history of trauma to the area. A purified protein derivative (tuberculin) skin test was negative at the time of examination. The patient’s medical history was remarkable for renal calculi. Her current medications included progesterone; estradiol; lansoprazole; prenatal vitamins; vitamins C and E; zinc; and calcium. The patient had no family history of sarcoidosis. Complete blood cell count, urinalysis, liver function tests, and angiotensin-converting enzyme levels were unremarkable. Pulmonary function tests were normal, and there was no evidence of sarcoidosis on chest radiography. Initial biopsy of the lesion revealed a perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated RBCs in the papillary dermis (Figure, D). Similar to patient 1, the infiltrate lacked cytologic atypia and did not involve the overlying epidermis. There was perivascular granulomatous inflammation in the mid dermis (Figure, E). Periodic acid–Schiff, Warthin-Starry, and AFB stains were negative for organisms. Polarization was negative for refractile foreign material.

The lesion was treated with clobetasol propionate ointment 0.05% twice daily for 6 weeks with transient improvement, but the lesion recurred upon treatment cessation. Subsequent treatment with intralesional triamcinolone resulted in slight improvement of the lesion. A therapeutic trial of targeted pulsed dye laser treatment was ineffective. The lesion gradually increased in size over the next year with no therapy, and a repeat biopsy revealed a lichenoid lymphohistiocytic infiltrate with abundant extravasated RBCs consistent with persistent PPD. A granulomatous infiltrate was not evident in the superficial shave biopsy specimen.

Patient 3

A 75-year-old white woman presented with scattered, speckled, cayenne pepper–like, red-brown macules on the legs. Two years prior to presentation, a few scattered symmetrical macules appeared on the dorsal aspects of the feet, which gradually increased in number to form larger confluent patches that spread to the lower legs. The patient denied itching or burning but reported that the patches became painful when scratched and were aggravated by sun exposure. Her medical history was remarkable for asthma, chronic renal insufficiency, coronary artery disease, Barrett esophagus, obstructive sleep apnea, hypothyroidism, renal calculi, type 2 diabetes mellitus, and hyperlipidemia. Her current medications included carvedilol, valsartan, levothyroxine, aspirin, clopidogrel, furosemide, nitrofurantoin, temazepam, insulin, ezetimibe-simvastatin, and lansoprazole. Computed tomography of the chest revealed no signs of sarcoidosis. Pulmonary function tests revealed moderate obstructive lung disease. An ophthalmology examination showed no evidence of sarcoidosis. Laboratory results revealed an elevated glucose, blood urea nitrogen, creatinine, and triglyceride levels, as well as low hematocrit and vitamin D levels. Urinalysis, thyroid-stimulating hormone (thyrotropin) test, liver function tests, angiotensin-converting enzyme test, hepatitis B surface antigen, and IFN-g release assay were normal.

Histologic examination of a punch biopsy specimen revealed an inflammatory infiltrate confined to the papillary dermis. This infiltrate was comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated RBC extravasation and intimately associated granulomas (Figure, F). Additional inflammation in the deeper aspects of the dermis was not identified. Periodic acid–Schiff, AFB, and Fite stains were negative for organisms. Polarization was negative for refractile foreign material.

A 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (A). Lichenoid lymphohistiocytic infiltrate in the papillary dermis with marked red blood cell extravasation (B)(H&E, original magnification ×20). Superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised of epithelioid histiocytes in the mid and deep dermis (C)(H&E, original magnification ×20). Perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated red blood cells in the papillary dermis (D)(H&E, original magnification ×10). Perivascular lymphohistiocytic inflammation with epithelioid granulomas in the mid dermis (E)(H&E, original magnification ×20). Lymphohistiocytic inflammation in the papillary dermis comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated red blood cell extravasation and intimately associated granulomas (F)(H&E, original magnification ×20).

The patient was treated with topical steroids and minocycline 50 mg twice daily without improvement. The lesions improved after the patient underwent treatment with oral corticosteroids for pulmonary disease.

Comment

Pigmented purpuric dermatoses comprise a spectrum of clinical and pathologic conditions.^1,2 Granulomatous PPD is a much less common variant, characterized by a granulomatous infiltrate admixed with PPD. We report 3 additional cases and review the literature on this rare and interesting variant of PPD.

We noted several unifying clinicopathologic features among our patients and those previously reported in the literature (Table).^3-7 Including our cases, our review yielded 13 GPPD patients ranging in age from 9 to 75 years, with a mean age of 49.1 years. Two of our patients—patients 1 and 3—were the youngest and oldest patients, respectively, among the cases we reviewed. The majority of the cases we reviewed included patients of East Asian descent (6 Taiwanese; 2 Japanese; 1 Korean) as well as 4 white patients. No distinctive gender predilection was apparent, as our review included 8 females and 5 males.

Our review revealed that GPPD lesions typically involve the lower extremities and usually are asymptomatic, with the exception of occasional pruritus. Additional lesions have been reported on the dorsal aspect of the hands, and 1 case noted exclusive involvement of the wrist.⁶ Lesions of GPPD can range in their clinical appearance. Three of 13 patients presented with purpuric papules and 2 had brown pigmentation with hemorrhagic papules^3,4,6; the remaining 8 patients had erythematous or brown macules, papules, or plaques.^5-7 The most commonly associated disease condition was hyperlipidemia, which was reported in 7 of 13 cases.^5-7 Additional reported comorbidities included meningioma, renal calculi, obesity, hypertension, diabetes mellitus, chronic obstructive pulmonary disease, hepatitis C virus, ulcerative colitis, thrombocytopenia, and hyperuricemia. Reported serologic abnormalities included a rare positive antinuclear antibody, rheumatoid factor, and cryoglobulins.^3,6 Therapeutic efficacy in the management of GPPD has not been well described; however, for the rare cases in which therapies were described, they were largely unsuccessful, with 1 patient exhibiting spontaneous improvement.^3,4

Granulomatous PPD also appears to exhibit a range of histologic findings. All cases of GPPD shared fundamental components, such as a brisk perivascular infiltrate accompanied by RBC extravasation with variable hemosiderin-laden macrophages and a granulomatous infiltrate. All of the reports we reviewed described an intimate association between these components, with the granulomas being essentially superimposed on typical PPD. As for other types of PPD, obvious vasculitis characterized by a vasculocentric inflammatory infiltrate and evidence of vascular injury, such as fibrinoid necrosis of the vessel wall, has not been described in GPPD.^3-7 Finally, histologic changes suggestive of a relationship with cutaneous T-cell lymphoma, cytologic atypia, and epidermotropism have been described for some forms of PPD but have not been described for GPPD.^3-8

Our case reports expand the histologic spectrum of GPPD. Although patient 3 exhibited a relatively intimate association of granulomas and PPD, 2 of our cases (patients 1 and 2) demonstrated a granulomatous infiltrate in the mid to deep dermis, which is separate from the more superficially situated lichenoid lymphohistiocytic infiltrate, RBC extravasation, and hemosiderin-laden macrophages noted in the papillary dermis. Considered along with the absence of an obvious clinicopathologic explanation for the granulomatous infiltrates (eg, polarizable material, infectious organisms, systemic disease), these 2 cases (patients 1 and 2) suggest a composite form of PPD that combines the lichenoid pattern of PPD of Gougerot and Blum with a deep granulomatous component of GPPD. The importance of this distinction lies in the potential for physicians to overlook this potentially informative histologic pattern if only a superficial biopsy is performed. The clinical relevance is unclear; however, in our experience, it has been challenging to treat this relatively small subset of patients who have exhibited a limited response to treatment with topical steroids, intralesional steroids, pulsed dye laser, and vitamin supplementation.

The cause of the granulomatous infiltrate in GPPD is poorly understood. Seven of 13 cases included in our review occurred in patients with a history of hyperlipidemia.^5-7 Some have postulated that the constellation of findings of GPPD in hyperlipidemic patients reflects an underlying vascular injury process induced by lipid deposition in the endothelial cells with subsequent RBC extravasation and a secondary granulomatous response to the lipid deposits.^6,7 However, given the occurrence of GPPD in patients without hyperlipidemia, other mechanisms also must be considered in the pathogenesis of GPPD, including a reaction to medications, systemic diseases, and infectious etiologies (eg, hepatitis B virus).^4,6 As additional cases are described in the literature, other unifying clinical etiologies for this histopathologic reaction pattern may emerge.

Conclusion

Granulomatous PPD may comprise an underrecognized variant of PPD in cases when only a superficial biopsy is evaluated. Clinicians and pathologists should be aware of this variant, and in refractory cases of PPD, deeper sampling may be warranted to identify granulomas.

Pigmented purpuric dermatoses (PPDs) are a group of common chronic disorders characterized by speckled, cayenne pepper–like petechiae and orange-brown discoloration of the skin resulting from capillaritis.¹ Pigmented purpuric dermatoses typically occur in the absence of underlying vascular insufficiency or other hematologic dysfunction. The 5 well-known clinicopathologic variants of PPD include Schamberg disease; purpura annularis telangiectodes of Majocchi; pigmented purpuric lichenoid dermatitis of Gougerot and Blum; eczematoidlike purpura of Doucas and Kapetanakis; and lichen aureus.² All PPDs share common characteristic clinical and histologic features. Clinically, patients generally present with symmetric petechiae and/or pigmented macules. All 5 PPD variants share similar histologic findings, including a vasculocentric lymphocytic infiltrate in the papillary dermis, swelling of the endothelial cells, erythrocyte extravasation, and often hemosiderin-laden macrophages.¹ Despite these clinical and histopathologic similarities, each variant contains additional distinctive features, such as telangiectasia (purpura annularis telangiectodes of Majocchi), a lichenoid infiltrate (pigmented purpuric lichenoid dermatitis of Gougerot and Blum), eczematous changes (eczematoidlike purpura of Doucas and Kapetanakis), and marked hemosiderin deposition (lichen aureus).

Granulomatous pigmented purpuric dermatosis (GPPD) is a rare variant of PPD.^3-7 Clinically, these lesions appear similar to other PPDs; however, in addition to the characteristic changes associated with conventional PPD, histologic examination of GPPD reveals a granulomatous inflammatory reaction pattern. Although the pathogenesis of GPPD is not well understood, its association with hyperlipidemia may suggest a granulomatous response to capillaritis mediated by lipid deposition in the microvasculature.^6,7

We present 3 cases of GPPD and provide a review of the literature. In all of our patients, biopsy specimens were fixed in 10% buffered formalin and embedded in paraffin by standard methodologies, and all stains were performed on sections by standard methodologies. Based on a PubMed search of articles indexed for MEDLINE using the terms granulomatous pigmented purpuric dermatosis, sarcoidosis, pigmented purpuric dermatosis, granulomas, and pigmented purpuric dermatosis, we review 5 additional reports describing 10 total patients.^3-7

Case Reports

Patient 1

A 9-year-old white boy presented with a 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (Figure, A). The lesion appeared 3 to 4 years prior to presentation but had become progressively darker and centrally indurated over the last 2 years. The patient and his mother denied any history of trauma to the area. His medical history was unremarkable, and his current medications included fish oil and multivitamin tablets.

Histologic examination of a punch biopsy specimen taken from the center of the lesion revealed a lichenoid lymphohistiocytic infiltrate with marked red blood cell (RBC) extravasation and associated hemosiderin-laden macrophages. The lymphocytes comprising this infiltrate lacked cytologic atypia and exhibited minimal epidermotropism (Figure, B). Additionally, there was a superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised ofepithelioid histiocytes in the mid and deep dermis (Figure, C). Periodic acid–Schiff, acid-fast bacilli (AFB), and Fite stains were negative for organisms. Polarization was negative for refractile foreign material. Due to the patient’s age, no treatment was performed, and the lesion remains unchanged 1 year after biopsy.

Patient 2

A 49-year-old white woman presented with a 2-cm yellow-brown patch with a faint, nonblanchable, violaceous center on the right lateral thigh of 4 months’ duration. The patch initially appeared as a small asymptomatic purple papule. The patient denied any history of trauma to the area. A purified protein derivative (tuberculin) skin test was negative at the time of examination. The patient’s medical history was remarkable for renal calculi. Her current medications included progesterone; estradiol; lansoprazole; prenatal vitamins; vitamins C and E; zinc; and calcium. The patient had no family history of sarcoidosis. Complete blood cell count, urinalysis, liver function tests, and angiotensin-converting enzyme levels were unremarkable. Pulmonary function tests were normal, and there was no evidence of sarcoidosis on chest radiography. Initial biopsy of the lesion revealed a perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated RBCs in the papillary dermis (Figure, D). Similar to patient 1, the infiltrate lacked cytologic atypia and did not involve the overlying epidermis. There was perivascular granulomatous inflammation in the mid dermis (Figure, E). Periodic acid–Schiff, Warthin-Starry, and AFB stains were negative for organisms. Polarization was negative for refractile foreign material.

The lesion was treated with clobetasol propionate ointment 0.05% twice daily for 6 weeks with transient improvement, but the lesion recurred upon treatment cessation. Subsequent treatment with intralesional triamcinolone resulted in slight improvement of the lesion. A therapeutic trial of targeted pulsed dye laser treatment was ineffective. The lesion gradually increased in size over the next year with no therapy, and a repeat biopsy revealed a lichenoid lymphohistiocytic infiltrate with abundant extravasated RBCs consistent with persistent PPD. A granulomatous infiltrate was not evident in the superficial shave biopsy specimen.

Patient 3

A 75-year-old white woman presented with scattered, speckled, cayenne pepper–like, red-brown macules on the legs. Two years prior to presentation, a few scattered symmetrical macules appeared on the dorsal aspects of the feet, which gradually increased in number to form larger confluent patches that spread to the lower legs. The patient denied itching or burning but reported that the patches became painful when scratched and were aggravated by sun exposure. Her medical history was remarkable for asthma, chronic renal insufficiency, coronary artery disease, Barrett esophagus, obstructive sleep apnea, hypothyroidism, renal calculi, type 2 diabetes mellitus, and hyperlipidemia. Her current medications included carvedilol, valsartan, levothyroxine, aspirin, clopidogrel, furosemide, nitrofurantoin, temazepam, insulin, ezetimibe-simvastatin, and lansoprazole. Computed tomography of the chest revealed no signs of sarcoidosis. Pulmonary function tests revealed moderate obstructive lung disease. An ophthalmology examination showed no evidence of sarcoidosis. Laboratory results revealed an elevated glucose, blood urea nitrogen, creatinine, and triglyceride levels, as well as low hematocrit and vitamin D levels. Urinalysis, thyroid-stimulating hormone (thyrotropin) test, liver function tests, angiotensin-converting enzyme test, hepatitis B surface antigen, and IFN-g release assay were normal.

Histologic examination of a punch biopsy specimen revealed an inflammatory infiltrate confined to the papillary dermis. This infiltrate was comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated RBC extravasation and intimately associated granulomas (Figure, F). Additional inflammation in the deeper aspects of the dermis was not identified. Periodic acid–Schiff, AFB, and Fite stains were negative for organisms. Polarization was negative for refractile foreign material.

A 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (A). Lichenoid lymphohistiocytic infiltrate in the papillary dermis with marked red blood cell extravasation (B)(H&E, original magnification ×20). Superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised of epithelioid histiocytes in the mid and deep dermis (C)(H&E, original magnification ×20). Perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated red blood cells in the papillary dermis (D)(H&E, original magnification ×10). Perivascular lymphohistiocytic inflammation with epithelioid granulomas in the mid dermis (E)(H&E, original magnification ×20). Lymphohistiocytic inflammation in the papillary dermis comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated red blood cell extravasation and intimately associated granulomas (F)(H&E, original magnification ×20).

The patient was treated with topical steroids and minocycline 50 mg twice daily without improvement. The lesions improved after the patient underwent treatment with oral corticosteroids for pulmonary disease.

Comment

Pigmented purpuric dermatoses comprise a spectrum of clinical and pathologic conditions.^1,2 Granulomatous PPD is a much less common variant, characterized by a granulomatous infiltrate admixed with PPD. We report 3 additional cases and review the literature on this rare and interesting variant of PPD.

We noted several unifying clinicopathologic features among our patients and those previously reported in the literature (Table).^3-7 Including our cases, our review yielded 13 GPPD patients ranging in age from 9 to 75 years, with a mean age of 49.1 years. Two of our patients—patients 1 and 3—were the youngest and oldest patients, respectively, among the cases we reviewed. The majority of the cases we reviewed included patients of East Asian descent (6 Taiwanese; 2 Japanese; 1 Korean) as well as 4 white patients. No distinctive gender predilection was apparent, as our review included 8 females and 5 males.

Our review revealed that GPPD lesions typically involve the lower extremities and usually are asymptomatic, with the exception of occasional pruritus. Additional lesions have been reported on the dorsal aspect of the hands, and 1 case noted exclusive involvement of the wrist.⁶ Lesions of GPPD can range in their clinical appearance. Three of 13 patients presented with purpuric papules and 2 had brown pigmentation with hemorrhagic papules^3,4,6; the remaining 8 patients had erythematous or brown macules, papules, or plaques.^5-7 The most commonly associated disease condition was hyperlipidemia, which was reported in 7 of 13 cases.^5-7 Additional reported comorbidities included meningioma, renal calculi, obesity, hypertension, diabetes mellitus, chronic obstructive pulmonary disease, hepatitis C virus, ulcerative colitis, thrombocytopenia, and hyperuricemia. Reported serologic abnormalities included a rare positive antinuclear antibody, rheumatoid factor, and cryoglobulins.^3,6 Therapeutic efficacy in the management of GPPD has not been well described; however, for the rare cases in which therapies were described, they were largely unsuccessful, with 1 patient exhibiting spontaneous improvement.^3,4

Granulomatous PPD also appears to exhibit a range of histologic findings. All cases of GPPD shared fundamental components, such as a brisk perivascular infiltrate accompanied by RBC extravasation with variable hemosiderin-laden macrophages and a granulomatous infiltrate. All of the reports we reviewed described an intimate association between these components, with the granulomas being essentially superimposed on typical PPD. As for other types of PPD, obvious vasculitis characterized by a vasculocentric inflammatory infiltrate and evidence of vascular injury, such as fibrinoid necrosis of the vessel wall, has not been described in GPPD.^3-7 Finally, histologic changes suggestive of a relationship with cutaneous T-cell lymphoma, cytologic atypia, and epidermotropism have been described for some forms of PPD but have not been described for GPPD.^3-8

Our case reports expand the histologic spectrum of GPPD. Although patient 3 exhibited a relatively intimate association of granulomas and PPD, 2 of our cases (patients 1 and 2) demonstrated a granulomatous infiltrate in the mid to deep dermis, which is separate from the more superficially situated lichenoid lymphohistiocytic infiltrate, RBC extravasation, and hemosiderin-laden macrophages noted in the papillary dermis. Considered along with the absence of an obvious clinicopathologic explanation for the granulomatous infiltrates (eg, polarizable material, infectious organisms, systemic disease), these 2 cases (patients 1 and 2) suggest a composite form of PPD that combines the lichenoid pattern of PPD of Gougerot and Blum with a deep granulomatous component of GPPD. The importance of this distinction lies in the potential for physicians to overlook this potentially informative histologic pattern if only a superficial biopsy is performed. The clinical relevance is unclear; however, in our experience, it has been challenging to treat this relatively small subset of patients who have exhibited a limited response to treatment with topical steroids, intralesional steroids, pulsed dye laser, and vitamin supplementation.

The cause of the granulomatous infiltrate in GPPD is poorly understood. Seven of 13 cases included in our review occurred in patients with a history of hyperlipidemia.^5-7 Some have postulated that the constellation of findings of GPPD in hyperlipidemic patients reflects an underlying vascular injury process induced by lipid deposition in the endothelial cells with subsequent RBC extravasation and a secondary granulomatous response to the lipid deposits.^6,7 However, given the occurrence of GPPD in patients without hyperlipidemia, other mechanisms also must be considered in the pathogenesis of GPPD, including a reaction to medications, systemic diseases, and infectious etiologies (eg, hepatitis B virus).^4,6 As additional cases are described in the literature, other unifying clinical etiologies for this histopathologic reaction pattern may emerge.

Conclusion

Granulomatous PPD may comprise an underrecognized variant of PPD in cases when only a superficial biopsy is evaluated. Clinicians and pathologists should be aware of this variant, and in refractory cases of PPD, deeper sampling may be warranted to identify granulomas.

Pigmented purpuric dermatoses (PPDs) are a group of common chronic disorders characterized by speckled, cayenne pepper–like petechiae and orange-brown discoloration of the skin resulting from capillaritis.¹ Pigmented purpuric dermatoses typically occur in the absence of underlying vascular insufficiency or other hematologic dysfunction. The 5 well-known clinicopathologic variants of PPD include Schamberg disease; purpura annularis telangiectodes of Majocchi; pigmented purpuric lichenoid dermatitis of Gougerot and Blum; eczematoidlike purpura of Doucas and Kapetanakis; and lichen aureus.² All PPDs share common characteristic clinical and histologic features. Clinically, patients generally present with symmetric petechiae and/or pigmented macules. All 5 PPD variants share similar histologic findings, including a vasculocentric lymphocytic infiltrate in the papillary dermis, swelling of the endothelial cells, erythrocyte extravasation, and often hemosiderin-laden macrophages.¹ Despite these clinical and histopathologic similarities, each variant contains additional distinctive features, such as telangiectasia (purpura annularis telangiectodes of Majocchi), a lichenoid infiltrate (pigmented purpuric lichenoid dermatitis of Gougerot and Blum), eczematous changes (eczematoidlike purpura of Doucas and Kapetanakis), and marked hemosiderin deposition (lichen aureus).

Granulomatous pigmented purpuric dermatosis (GPPD) is a rare variant of PPD.^3-7 Clinically, these lesions appear similar to other PPDs; however, in addition to the characteristic changes associated with conventional PPD, histologic examination of GPPD reveals a granulomatous inflammatory reaction pattern. Although the pathogenesis of GPPD is not well understood, its association with hyperlipidemia may suggest a granulomatous response to capillaritis mediated by lipid deposition in the microvasculature.^6,7

We present 3 cases of GPPD and provide a review of the literature. In all of our patients, biopsy specimens were fixed in 10% buffered formalin and embedded in paraffin by standard methodologies, and all stains were performed on sections by standard methodologies. Based on a PubMed search of articles indexed for MEDLINE using the terms granulomatous pigmented purpuric dermatosis, sarcoidosis, pigmented purpuric dermatosis, granulomas, and pigmented purpuric dermatosis, we review 5 additional reports describing 10 total patients.^3-7

Case Reports

Patient 1

A 9-year-old white boy presented with a 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (Figure, A). The lesion appeared 3 to 4 years prior to presentation but had become progressively darker and centrally indurated over the last 2 years. The patient and his mother denied any history of trauma to the area. His medical history was unremarkable, and his current medications included fish oil and multivitamin tablets.

Histologic examination of a punch biopsy specimen taken from the center of the lesion revealed a lichenoid lymphohistiocytic infiltrate with marked red blood cell (RBC) extravasation and associated hemosiderin-laden macrophages. The lymphocytes comprising this infiltrate lacked cytologic atypia and exhibited minimal epidermotropism (Figure, B). Additionally, there was a superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised ofepithelioid histiocytes in the mid and deep dermis (Figure, C). Periodic acid–Schiff, acid-fast bacilli (AFB), and Fite stains were negative for organisms. Polarization was negative for refractile foreign material. Due to the patient’s age, no treatment was performed, and the lesion remains unchanged 1 year after biopsy.

Patient 2

A 49-year-old white woman presented with a 2-cm yellow-brown patch with a faint, nonblanchable, violaceous center on the right lateral thigh of 4 months’ duration. The patch initially appeared as a small asymptomatic purple papule. The patient denied any history of trauma to the area. A purified protein derivative (tuberculin) skin test was negative at the time of examination. The patient’s medical history was remarkable for renal calculi. Her current medications included progesterone; estradiol; lansoprazole; prenatal vitamins; vitamins C and E; zinc; and calcium. The patient had no family history of sarcoidosis. Complete blood cell count, urinalysis, liver function tests, and angiotensin-converting enzyme levels were unremarkable. Pulmonary function tests were normal, and there was no evidence of sarcoidosis on chest radiography. Initial biopsy of the lesion revealed a perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated RBCs in the papillary dermis (Figure, D). Similar to patient 1, the infiltrate lacked cytologic atypia and did not involve the overlying epidermis. There was perivascular granulomatous inflammation in the mid dermis (Figure, E). Periodic acid–Schiff, Warthin-Starry, and AFB stains were negative for organisms. Polarization was negative for refractile foreign material.

The lesion was treated with clobetasol propionate ointment 0.05% twice daily for 6 weeks with transient improvement, but the lesion recurred upon treatment cessation. Subsequent treatment with intralesional triamcinolone resulted in slight improvement of the lesion. A therapeutic trial of targeted pulsed dye laser treatment was ineffective. The lesion gradually increased in size over the next year with no therapy, and a repeat biopsy revealed a lichenoid lymphohistiocytic infiltrate with abundant extravasated RBCs consistent with persistent PPD. A granulomatous infiltrate was not evident in the superficial shave biopsy specimen.

Patient 3

A 75-year-old white woman presented with scattered, speckled, cayenne pepper–like, red-brown macules on the legs. Two years prior to presentation, a few scattered symmetrical macules appeared on the dorsal aspects of the feet, which gradually increased in number to form larger confluent patches that spread to the lower legs. The patient denied itching or burning but reported that the patches became painful when scratched and were aggravated by sun exposure. Her medical history was remarkable for asthma, chronic renal insufficiency, coronary artery disease, Barrett esophagus, obstructive sleep apnea, hypothyroidism, renal calculi, type 2 diabetes mellitus, and hyperlipidemia. Her current medications included carvedilol, valsartan, levothyroxine, aspirin, clopidogrel, furosemide, nitrofurantoin, temazepam, insulin, ezetimibe-simvastatin, and lansoprazole. Computed tomography of the chest revealed no signs of sarcoidosis. Pulmonary function tests revealed moderate obstructive lung disease. An ophthalmology examination showed no evidence of sarcoidosis. Laboratory results revealed an elevated glucose, blood urea nitrogen, creatinine, and triglyceride levels, as well as low hematocrit and vitamin D levels. Urinalysis, thyroid-stimulating hormone (thyrotropin) test, liver function tests, angiotensin-converting enzyme test, hepatitis B surface antigen, and IFN-g release assay were normal.

Histologic examination of a punch biopsy specimen revealed an inflammatory infiltrate confined to the papillary dermis. This infiltrate was comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated RBC extravasation and intimately associated granulomas (Figure, F). Additional inflammation in the deeper aspects of the dermis was not identified. Periodic acid–Schiff, AFB, and Fite stains were negative for organisms. Polarization was negative for refractile foreign material.

A 3-cm asymptomatic light brown patch with a nonblanching violaceous center on the right posterior thigh that was studded with pinpoint yellow papules (A). Lichenoid lymphohistiocytic infiltrate in the papillary dermis with marked red blood cell extravasation (B)(H&E, original magnification ×20). Superficial and deep perivascular mononuclear inflammatory infiltrate intermixed with numerous small granulomas comprised of epithelioid histiocytes in the mid and deep dermis (C)(H&E, original magnification ×20). Perivascular and interstitial lymphohistiocytic infiltrate with abundant extravasated red blood cells in the papillary dermis (D)(H&E, original magnification ×10). Perivascular lymphohistiocytic inflammation with epithelioid granulomas in the mid dermis (E)(H&E, original magnification ×20). Lymphohistiocytic inflammation in the papillary dermis comprised of an admixture of lymphocytes and histiocytes in a perivascular distribution with associated red blood cell extravasation and intimately associated granulomas (F)(H&E, original magnification ×20).

The patient was treated with topical steroids and minocycline 50 mg twice daily without improvement. The lesions improved after the patient underwent treatment with oral corticosteroids for pulmonary disease.

Comment

Pigmented purpuric dermatoses comprise a spectrum of clinical and pathologic conditions.^1,2 Granulomatous PPD is a much less common variant, characterized by a granulomatous infiltrate admixed with PPD. We report 3 additional cases and review the literature on this rare and interesting variant of PPD.

We noted several unifying clinicopathologic features among our patients and those previously reported in the literature (Table).^3-7 Including our cases, our review yielded 13 GPPD patients ranging in age from 9 to 75 years, with a mean age of 49.1 years. Two of our patients—patients 1 and 3—were the youngest and oldest patients, respectively, among the cases we reviewed. The majority of the cases we reviewed included patients of East Asian descent (6 Taiwanese; 2 Japanese; 1 Korean) as well as 4 white patients. No distinctive gender predilection was apparent, as our review included 8 females and 5 males.

Our review revealed that GPPD lesions typically involve the lower extremities and usually are asymptomatic, with the exception of occasional pruritus. Additional lesions have been reported on the dorsal aspect of the hands, and 1 case noted exclusive involvement of the wrist.⁶ Lesions of GPPD can range in their clinical appearance. Three of 13 patients presented with purpuric papules and 2 had brown pigmentation with hemorrhagic papules^3,4,6; the remaining 8 patients had erythematous or brown macules, papules, or plaques.^5-7 The most commonly associated disease condition was hyperlipidemia, which was reported in 7 of 13 cases.^5-7 Additional reported comorbidities included meningioma, renal calculi, obesity, hypertension, diabetes mellitus, chronic obstructive pulmonary disease, hepatitis C virus, ulcerative colitis, thrombocytopenia, and hyperuricemia. Reported serologic abnormalities included a rare positive antinuclear antibody, rheumatoid factor, and cryoglobulins.^3,6 Therapeutic efficacy in the management of GPPD has not been well described; however, for the rare cases in which therapies were described, they were largely unsuccessful, with 1 patient exhibiting spontaneous improvement.^3,4

Granulomatous PPD also appears to exhibit a range of histologic findings. All cases of GPPD shared fundamental components, such as a brisk perivascular infiltrate accompanied by RBC extravasation with variable hemosiderin-laden macrophages and a granulomatous infiltrate. All of the reports we reviewed described an intimate association between these components, with the granulomas being essentially superimposed on typical PPD. As for other types of PPD, obvious vasculitis characterized by a vasculocentric inflammatory infiltrate and evidence of vascular injury, such as fibrinoid necrosis of the vessel wall, has not been described in GPPD.^3-7 Finally, histologic changes suggestive of a relationship with cutaneous T-cell lymphoma, cytologic atypia, and epidermotropism have been described for some forms of PPD but have not been described for GPPD.^3-8

Our case reports expand the histologic spectrum of GPPD. Although patient 3 exhibited a relatively intimate association of granulomas and PPD, 2 of our cases (patients 1 and 2) demonstrated a granulomatous infiltrate in the mid to deep dermis, which is separate from the more superficially situated lichenoid lymphohistiocytic infiltrate, RBC extravasation, and hemosiderin-laden macrophages noted in the papillary dermis. Considered along with the absence of an obvious clinicopathologic explanation for the granulomatous infiltrates (eg, polarizable material, infectious organisms, systemic disease), these 2 cases (patients 1 and 2) suggest a composite form of PPD that combines the lichenoid pattern of PPD of Gougerot and Blum with a deep granulomatous component of GPPD. The importance of this distinction lies in the potential for physicians to overlook this potentially informative histologic pattern if only a superficial biopsy is performed. The clinical relevance is unclear; however, in our experience, it has been challenging to treat this relatively small subset of patients who have exhibited a limited response to treatment with topical steroids, intralesional steroids, pulsed dye laser, and vitamin supplementation.

The cause of the granulomatous infiltrate in GPPD is poorly understood. Seven of 13 cases included in our review occurred in patients with a history of hyperlipidemia.^5-7 Some have postulated that the constellation of findings of GPPD in hyperlipidemic patients reflects an underlying vascular injury process induced by lipid deposition in the endothelial cells with subsequent RBC extravasation and a secondary granulomatous response to the lipid deposits.^6,7 However, given the occurrence of GPPD in patients without hyperlipidemia, other mechanisms also must be considered in the pathogenesis of GPPD, including a reaction to medications, systemic diseases, and infectious etiologies (eg, hepatitis B virus).^4,6 As additional cases are described in the literature, other unifying clinical etiologies for this histopathologic reaction pattern may emerge.

Conclusion

Granulomatous PPD may comprise an underrecognized variant of PPD in cases when only a superficial biopsy is evaluated. Clinicians and pathologists should be aware of this variant, and in refractory cases of PPD, deeper sampling may be warranted to identify granulomas.