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Background
Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal (GI) tract, accounting for approximately 1–2% of GI cancers. Hypoglycemia in patients with GIST is an uncommon and diagnostically challenging presentation, often involving a broad differential diagnosis. This case report explores the diagnostic difficulties encountered in managing persistent hypoglycemia in a patient with a history of advanced GIST.
Case Presentation
An 80-year-old male with a history of stage IV GIST, diagnosed in 2010, presented with persistent symptomatic hypoglycemia. His medical history included extensive abdominal disease, managed with multiple interventions: esophagogastrostomy, left lateral liver resection, a Whipple procedure, and Y-90 radioembolization. He received adjuvant imatinib therapy, which was discontinued in April 2024 due to significant adverse effects, including anasarca. In 2025, the patient developed progressive hypoglycemia, ultimately requiring continuous D10 infusion to maintain euglycemia, prompting an endocrinology evaluation. The initial diagnostic workup included cortisol, insulin, C-peptide levels, and IGF-1/IGF-2 ratio ruling out insulinoma, adrenal insufficiency, and GISTrelated paraneoplastic syndrome. Imaging studies, including PET and CT, showed no radiological evidence of recurrent GIST. Treatment with octreotide infusion resulted in minimal improvement, whereas daily corticosteroid therapy significantly alleviated the patient’s symptoms. The etiology of hypoglycemia remains elusive, with potential causes under consideration including Y-90 radioembolization-induced damage to glucagon-producing cells, immunotherapy-related adverse effects, or radiologically occult GIST. Insulin autoantibody testing is pending, and the case remains under active investigation, highlighting the diagnostic complexity of hypoglycemia in advanced GIST.
Discussion
Hypoglycemia in the context of GIST is a rare and poorly understood phenomenon. Potential mechanisms include paraneoplastic syndromes, such as non-islet cell tumor hypoglycemia (NICTH) mediated by IGF-2, or treatment-related effects, such as radiation-induced pancreatic or hepatic dysfunction. In this case, the absence of detectable IGF-2 abnormalities and negative imaging complicates the diagnosis. The lack of response to octreotide indicates that somatostatin receptor-mediated pathways may not be involved. The discontinuation of imatinib and prior Y-90 radioembolization further broadens the differential, as both could contribute to metabolic dysregulation.
Conclusions
This case illustrates the need for a systematic and multidisciplinary approach to evaluate hypoglycemia in patients with advanced GIST.
Background
Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal (GI) tract, accounting for approximately 1–2% of GI cancers. Hypoglycemia in patients with GIST is an uncommon and diagnostically challenging presentation, often involving a broad differential diagnosis. This case report explores the diagnostic difficulties encountered in managing persistent hypoglycemia in a patient with a history of advanced GIST.
Case Presentation
An 80-year-old male with a history of stage IV GIST, diagnosed in 2010, presented with persistent symptomatic hypoglycemia. His medical history included extensive abdominal disease, managed with multiple interventions: esophagogastrostomy, left lateral liver resection, a Whipple procedure, and Y-90 radioembolization. He received adjuvant imatinib therapy, which was discontinued in April 2024 due to significant adverse effects, including anasarca. In 2025, the patient developed progressive hypoglycemia, ultimately requiring continuous D10 infusion to maintain euglycemia, prompting an endocrinology evaluation. The initial diagnostic workup included cortisol, insulin, C-peptide levels, and IGF-1/IGF-2 ratio ruling out insulinoma, adrenal insufficiency, and GISTrelated paraneoplastic syndrome. Imaging studies, including PET and CT, showed no radiological evidence of recurrent GIST. Treatment with octreotide infusion resulted in minimal improvement, whereas daily corticosteroid therapy significantly alleviated the patient’s symptoms. The etiology of hypoglycemia remains elusive, with potential causes under consideration including Y-90 radioembolization-induced damage to glucagon-producing cells, immunotherapy-related adverse effects, or radiologically occult GIST. Insulin autoantibody testing is pending, and the case remains under active investigation, highlighting the diagnostic complexity of hypoglycemia in advanced GIST.
Discussion
Hypoglycemia in the context of GIST is a rare and poorly understood phenomenon. Potential mechanisms include paraneoplastic syndromes, such as non-islet cell tumor hypoglycemia (NICTH) mediated by IGF-2, or treatment-related effects, such as radiation-induced pancreatic or hepatic dysfunction. In this case, the absence of detectable IGF-2 abnormalities and negative imaging complicates the diagnosis. The lack of response to octreotide indicates that somatostatin receptor-mediated pathways may not be involved. The discontinuation of imatinib and prior Y-90 radioembolization further broadens the differential, as both could contribute to metabolic dysregulation.
Conclusions
This case illustrates the need for a systematic and multidisciplinary approach to evaluate hypoglycemia in patients with advanced GIST.
Background
Gastrointestinal stromal tumors (GISTs) are rare neoplasms of the gastrointestinal (GI) tract, accounting for approximately 1–2% of GI cancers. Hypoglycemia in patients with GIST is an uncommon and diagnostically challenging presentation, often involving a broad differential diagnosis. This case report explores the diagnostic difficulties encountered in managing persistent hypoglycemia in a patient with a history of advanced GIST.
Case Presentation
An 80-year-old male with a history of stage IV GIST, diagnosed in 2010, presented with persistent symptomatic hypoglycemia. His medical history included extensive abdominal disease, managed with multiple interventions: esophagogastrostomy, left lateral liver resection, a Whipple procedure, and Y-90 radioembolization. He received adjuvant imatinib therapy, which was discontinued in April 2024 due to significant adverse effects, including anasarca. In 2025, the patient developed progressive hypoglycemia, ultimately requiring continuous D10 infusion to maintain euglycemia, prompting an endocrinology evaluation. The initial diagnostic workup included cortisol, insulin, C-peptide levels, and IGF-1/IGF-2 ratio ruling out insulinoma, adrenal insufficiency, and GISTrelated paraneoplastic syndrome. Imaging studies, including PET and CT, showed no radiological evidence of recurrent GIST. Treatment with octreotide infusion resulted in minimal improvement, whereas daily corticosteroid therapy significantly alleviated the patient’s symptoms. The etiology of hypoglycemia remains elusive, with potential causes under consideration including Y-90 radioembolization-induced damage to glucagon-producing cells, immunotherapy-related adverse effects, or radiologically occult GIST. Insulin autoantibody testing is pending, and the case remains under active investigation, highlighting the diagnostic complexity of hypoglycemia in advanced GIST.
Discussion
Hypoglycemia in the context of GIST is a rare and poorly understood phenomenon. Potential mechanisms include paraneoplastic syndromes, such as non-islet cell tumor hypoglycemia (NICTH) mediated by IGF-2, or treatment-related effects, such as radiation-induced pancreatic or hepatic dysfunction. In this case, the absence of detectable IGF-2 abnormalities and negative imaging complicates the diagnosis. The lack of response to octreotide indicates that somatostatin receptor-mediated pathways may not be involved. The discontinuation of imatinib and prior Y-90 radioembolization further broadens the differential, as both could contribute to metabolic dysregulation.
Conclusions
This case illustrates the need for a systematic and multidisciplinary approach to evaluate hypoglycemia in patients with advanced GIST.