Retroperitoneal Solitary Fibrous Tumor Induced Hypoglycemia Associated with High Molecular Weight Insulin-like Growth Factor II

Abstract

A 65-year-old man presented with frequent episodes of hypoglycemia and unconsciousness. Hypoglycemia was accompanied by undetectable serum insulin and C-peptide levels and a high serum insulin-like growth factor (IGF)-II level. He was found to have a retroperitoneal solitary fibrous tumor. He underwent successful resection of the tumor and had no hypoglycemic episodes after the operation. Immunohistochemical analysis revealed positive immunostaining for IGF-II in tumor cells. The presence of the high-molecular-weight form of IGF-II in the patient’s serum was confirmed by immunoblotting, suggesting that his hypoglycemia was due to an increase in the plasma level of IGF-II secreted by the tumor.