Insulomas and multiple endocrine neoplasia.

Seventy-eight patients with insuloma diagnosed between 1959 and 1968 in Sweden were studied for neoplasia in other organs. Twenty-one patients had beta-cell islet tumors, 14 Zollinger-Ellison's syndrome and non-beta-cell islet tumors, while no endocrine activity was demonstrated in 43 patients. Of the last-mentioned group, 9 patients had co-existing disease of other endocrine organs. In 10 patients, non-endocrine organs were found to be affected by malignant diseases. It appears probable that the tissue of the pancreatic islets, like parathyroid tissue, can react with hyperplasia with a later development of adenoma, secondary to tumors in other organs.