Insulinoma and glucagonoma.

Abstract

T HE ISLETS OF LANGERHANS are clusters of endocrine cells, distributed throughout the exocrine pancreas, representing approximately 1% of its mass. Four types of cells, A, B, D, and P cells, distinguished by their respective locations within the islets and by the size, shape, and hormone content of their secretory granules have been identified in adult islets. All four cell types can develop into tumors, the glucagonsecretion A cells into glucagonomas, the insulinsecreting B cells into insulinomas, the somatostatin-secreting D cells into somatostatinomas, and the pancreatic polypeptide-secreting P cells into PPomas. Insulinomas, glucagonomas, and somatostatinomas are associated with distinct clinical syndromes. This is apparently not the case with PPomas as the physiologic function of human pancreatic poiypeptide remains to be established. In this chapter, the clinical and pathological features of two islet cell tumors, insulinomas“’ and glucagonomas, are briefly reviewed.