SUN-301 - Breaking the Cycle: Steroid-Responsive IGF-2-Mediated Hypoglycemia Secondary to Metastatic Hemangiopericytoma

Doege–Potter syndrome is a rare paraneoplastic cause of hypoglycemia in solitary fibrous tumors such as hemangiopericytoma, mediated by secretion of high–molecular weight IGF-2. We describe a metastatic hemangiopericytoma causing steroid-responsive hypoglycemia, where glucocorticoid therapy stabilized glucose and enabled long-term endocrine management when surgery was not feasible.

A 55-year-old man with metastatic malignant hemangiopericytoma involving the liver, pancreas, sacrum, suprapubic region, and brain presented with altered mental status, right upper-quadrant pain, and recurrent hypoglycemia. He was reported to have several days of progressive lethargy, poor oral intake, and dependence on oral glucose supplementation. He was not receiving active cancer-directed therapy. On presentation, serum glucose was 83 mg/dL, sodium 122 mmol/L, AST 109 U/L, ALT 83 U/L, and alkaline phosphatase 854 U/L. CT imaging demonstrated extensive hepatic and pancreatic metastases, pulmonary nodules, lytic bone lesions, and worsening vasogenic edema of the right temporal lobe. Endocrinology was consulted for persistent fasting hypoglycemia despite continuous dextrose infusion. Prior evaluation revealed IGF-2 = 111 ng/mL with IGF-1 < 20 ng/mL, yielding a ratio > 5, consistent with IGF-2–mediated non-islet cell tumor hypoglycemia. Repeat testing during this admission demonstrated IGF-2 = 155 ng/mL and IGF-1 = 23 ng/mL (ratio = 6.7), confirming biochemical progression and strengthening the diagnosis. Given unreliable oral intake, intravenous dexamethasone 1 mg every 12 hours was initiated and later transitioned to oral prednisone 5 mg twice daily. Hypoglycemia resolved within 24 hours of steroid therapy and did not recur during hospitalization. As surgical debulking was infeasible due to widespread metastatic disease, the patient was discharged home on hospice with endocrinology follow-up for continued metabolic management.

IGF-2–mediated hypoglycemia, or Doege–Potter syndrome, is an exceptionally rare manifestation of metastatic hemangiopericytoma. Excess “big" IGF-2 suppresses insulin and IGF-1 activity, impairing glucose homeostasis and hepatic glycogenolysis. This case demonstrates the diagnostic utility of the IGF-2/IGF-1 ratio and highlights the effectiveness of glucocorticoids in controlling tumor-induced hypoglycemia. By reducing aberrant IGF-2 production, restoring IGF axis balance, and enhancing hepatic gluconeogenesis, glucocorticoids can offer a rapid, durable, and pragmatic solution when surgery or cytoreductive therapy is not possible. Prompt recognition of this paraneoplastic syndrome is essential to prevent recurrent neuroglycopenia and guide palliative endocrine management in advanced mesenchymal malignancy.

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