Carcinoid syndrome due to a malignant somatostatinoma.

Somatostatinoma is one of the rarest tumours of the endocrine pancreas. Cardinal manifestations of a somatostatinoma include gallstones, mild diabetes mellitus, steatorrhoea, diarrhoea and dyspepsia. Like any other pancreatic islet cell carcinoma, a somatostatinoma may also produce several different hormones such as adrenocorticotropic hormone, calcitonin, vasoactive intestinal polypeptide, pancreatic polypeptide, gastrin, insulin, and glucagon. In many cases, the clinical picture is dominated by the effect of these other hormones. We present a patient with somatostatinoma in which an immunocytochemical study of the specimens from pancreas and liver showed a weak positive reaction for gastrin besides a strong positive reaction for somatostatin. Interestingly, this patient also showed the signs of carcinoid syndrome which was successfully treated with octreotide.