The histo-logical appearance was that of a carcinoma. Although disseminated neoplastic disease was present hepatic involvement was minimal. The pancreas was free of tumor and the islet cell structure was normal. The amount of neoplastic tissue present was not massive. Insulin-like activity was demonstrated by the rat diaphragm method in the tissue extract. It is suggested that symptomatic hypoglycemia was aided by the elaboration of an insulin-like substance by the tumor.