Metastatic insulinoma with long survival and glucagonoma syndrome

In 1966, during cholecystectomy for cholecystolithiasis, a 56-year-old man was found to have islet-cell carcinoma metastatic to the liver; his fasting serum glucose level was normal. In 1971, he developed peptic ulcer disease and symptoms of fasting hypoglycemia; inappropriate secretion of insulin was shown. His primary pancreatic tumor was removed in 1973. During the next 9 years, his liver metastases continued to grow and his fasting serum glucose level was maintained at 35 to 116 mg/dL with diazoxide and hydrochlorothiazide therapy. In 1982, he developed clinical evidence of the glucagonoma syndrome, with glucagon levels between 4000 and 11 000 pg/mL. Since then, his fasting serum glucose level has been maintained at 58 to 119 mg/dL without medication. This patient has survived 17 years with a malignant insulinoma and without islet-cell chemotherapy. His course shows that malignant insulinomas may secrete other peptide hormones that can induce various clinical syndromes.