An elderly woman had dangerous low blood sugar because a rare tumor was pumping out too much IGF‑2. She couldn't have surgery, so doctors used radiation to shrink the tumor, gave her steroids and carbs at night, and her blood sugar and heart rhythm got much better.

Doege-Potter syndrome (DPS) is a rare paraneoplastic condition characterized by hypoglycemia resulting from the excessive secretion of insulin-like growth factor-2 (IGF-2) by a solitary fibrous tumor (SFT). This report presents an elderly patient with DPS complicated by severe cardiac conduction abnormalities, illustrating the clinical manifestation, therapeutic intervention, and multidisciplinary management strategy. A 78-year-old woman was diagnosed with DPS, presenting with loss of consciousness with a blood glucose level of 1.41 mmol/L, and hypoglycemia was resolved with intravenous glucose. The initial laboratory investigation revealed elevated insulin levels of 7.17 μIU/mL, with suppressed C-peptide levels of 0.09 ng/mL and insulin-like growth factor-1 (IGF-1) levels of 26.47 ng/mL. Thoracic computed tomography (CT) identified a 13.6 cm × 8.6 cm mass in the right lower thoracic cavity. CT-guided transthoracic biopsy confirmed SFT with immunohistochemical positivity for CD34 and STAT6. Electrocardiogram (ECG) demonstrated frequent atrial premature complexes (29,292/24 hours), short runs of atrial tachycardia (144/24 hours), and paroxysmal ventricular premature complexes. Echocardiography revealed severe aortic valve insufficiency. Following multidisciplinary team (MDT) consultation, the surgically ineligible patient received tumor-directed radiotherapy (60 Gy in 30 fractions), glucocorticoid replacement (hydrocortisone 40 mg daily), and overnight carbohydrate supplementation to alleviate hypoglycemia. At 18-month follow-up, serial chest CT showed tumor size reduction. Holter monitoring revealed a substantial reduction in atrial premature complexes (1,955/24 hours vs. baseline 29,292/24 hours). The patient exhibited no recurrence of hypoglycemic episodes. This report describes a case of DPS with refractory hypoglycemia complicated by severe cardiac structural and conduction abnormalities. Radiotherapy combined with endocrine intervention effectively controlled tumor-associated hypoglycemia in this surgically ineligible patient.