Non-Islet Cell Tumor Hypoglycemia Caused by Recurrent Pelvic Solitary Fibrous Tumor

Non-islet cell tumor hypoglycemia is a rare paraneoplastic condition caused by an extra-pancreatic tumor. We report a rare case of hypoglycemia caused by a relapsing pelvic solitary fibrous tumor associated with Big-IGF-2 production. A 72-year-old woman was admitted to our hospital because of loss of consciousness and hypoglycemia. She had a history of ovarian solitary fibrous tumor, which has relapsed. From investigation, serum levels of insulin and C-peptide were suppressed; IGF-1 was slightly reduced and IGF-2 was within the normal range, but the IGF-2: IGF-1 ratio was elevated, indicating the presence of Big-IGF-2 secreting non-islet cell tumor. Contrast-enhanced computed tomography (CT) showed a large pelvic mass. She was then submitted to surgical resection of the mass, which histologically proved to be a solitary fibrous tumor. Three months later, she remains asymptomatic. Non-islet cell tumor hypoglycemia should be considered in the differential diagnosis of patients presenting with tumors and recurrent hypoglycemia.