Non-Islet Cell Tumor Hypoglycemia Is Caused by Big IGF-II in a Patient with a Carcinosarcoma of the Uterus

We report a 72-year-old Japanese woman with severe hypoglycemia. The laboratory data, which revealed the suppression of serum insulin, suggested the existence of non-islet cell tumor hypoglycemia (NICTH). Abdominal computed tomography demonstrated the presence of a huge uterine tumor. The patient was treated with a continuous infusion of glucose, but died of sepsis on day 46. An autopsy revealed the pathological diagnosis to be a carcinosarcoma of the uterus. Interestingly, an immunohistochemical study discovered the expression of insulin-like growth factor (IGF)-II in both the carcinoma and sarcoma cells. In addition, an immunoblot analysis of blood samples revealed the presence of circulating big IGF-II. Therefore, this is a novel case of NICTH that was caused by a uterine carcinosarcoma.