Gastric Neuroendocrine Carcinoma with Non-islet Cell Tumor Hypoglycemia Associated with Enhanced Production of Insulin-like Growth Factor II

A 75-year-old man was admitted to the hospital with a loss of consciousness. His blood glucose level was 24 mg/dL. Abdominal computed tomography revealed multiple metastatic lesions in the liver, while upper endoscopy disclosed advanced gastric cancer. The hypoglycemia was refractory despite the administration of glucose and steroid therapy. The patient died within one month of admission. An autopsy revealed neuroendocrine-type gastric cancer, which, on examination with immunohistochemistry, was found to be negative for insulin and insulin-like growth factor I and positive for insulin-like growth factor II (IGF-II). The patient was diagnosed as having gastric cancer with non-islet cell tumor hypoglycemia (NICTH) caused by IGF-II.