Gastric cancer containing insulin and associated with hypoglycemia

A patient with gastric cancer associated with hypoglycemia is described. Immunoassay of acid alcohol tissue extract revealed the presence of 7.6 mU. insulin per gram wet tissue weight in the primary tumor which weighed 10 gm. No insulin was detected in the hepatic metastasis. The concentration of pancreatic insulin was decreased and the serum insulin level was not elevated. Tissue insulinase activity was virtually absent in the primary tumor, whereas the hepatic metastasis showed activity comparable to that of normal liver. It is difficult to assume, however, that the release of insulin from the primary tumor, which contained such small quantities of the hormone, could be the Bole cause of hypoglycemia. An additional mechanism(s) must have been involved in the causation of hypoglycemia in this patient.