Endocrine neoplasms of the pancreas: a clinicopathologic study of 24 cases and immunohistochemical remarks.

A total of 24 patients with endocrine neoplasms of the pancreas were clinicopathologically and immunohistochemically studied. They consisted of 18 patients with adenoma and 6 with carcinoma. Of the 24 patients, 13 developed attacks of hypoglycemia due to hyperinsulinemia, and 1 developed an uncontrollable duodenal ulcer caused by the hypersecretion of gastrin, however, the remaining 10 were asymptomatic. No prediction could be made as to the site of origin of the tumors. A clear difference was seen between adenoma and carcinoma in the size of the mass, the mean greatest diameter of the 18 adenoma cases being 1.7 cm, while that of the 6 carcinoma cases was 7.3 cm. One of the 13 insulinomas and a gastrinoma was malignant, while all 24 tumors were positive for neuron-specific enolase. The 13 insulinomas were diffusely positive for insulin and 5 were also shown to be focally immunoreactive for gastrin, with 3 also being immunoreactive for somatostatin and 2 for pancreatic polypeptide. The gastrinoma showed immunoreactivity for somatostatin, insulin, pancreatic polypeptide, and glucagon in addition to a positivity to gastrin. The above findings thus indicate the multiple hormone synthesis of endocrine neoplasms of the pancreas.