title: The endocrine cells of the pancreas and related tumours. Ultrastructural study and classification.
abstract: Up to seven endocrine cell types have been identified ultrastructurally in the pancreas, including glucagon A cells, insulin B cells, somatostatin D cells, pancreatic peptide F cells and 5-hydroxytryptamine EC cells. In addition, D1 cells, which have been proposed as the cell type producing VIP and possible P cells of unknown function are seen. Various patterns of endocrine cell differentiation have been found in 20 endocrine pancreatic tumours. Well and poorly differentiated B cells have been identified in 6 insulinomas, diagnostic G cells in 3 out of 7 gastrinomas, D1 and/or F cells in 7 diarrheogenic tumours. Moreover, cells apparently unrelated to the prevalent clinical syndrome have been noted in 8 of the 20 tumours. Granular non diagnostic cells (poorly diagnostic gastrin cells? D1 cells?) were particularly frequent in gastrinomas; agranular or poorly granular cells, either by "active" or "Stem cell" type, were present in nearly all tumours, particularly in diarrheogenic tumours, gastrinomas and malignant insulinomas. A cytological classification of pancreatic endocrine tumours is proposed.
mesh_terms: D007516:Adenoma, Islet Cell / Q000473:pathology*; D000818:Animals; D002415:Cats; D002454:Cell Differentiation; D004285:Dogs; D005755:Gastrins; D005934:Glucagon; D006168:Guinea Pigs; D006801:Humans; D007328:Insulin; D007515:Islets of Langerhans / Q000648:ultrastructure; D008854:Microscopy, Electron; D010190:Pancreatic Neoplasms / Q000145:classification / Q000473:pathology*; D012701:Serotonin; D013004:Somatostatin; D013552:Swine
chemical_list: D005755:Gastrins; D007328:Insulin; D012701:Serotonin; D013004:Somatostatin; D005934:Glucagon