Immunocytochemical and ultrastructural abnormalities of islet tissue in patients with VIP-producing tumors of the pancreas.
Nontumoral endocrine pancreas from three patients with malignant vasoactive intestinal polypeptide (VIP)-omas and the Verner-Morrison (watery diarrhea, hypokalemia, and hypoachlorhydria) syndrome was studied immunocytochemically, ultrastructurally, and morphometrically. Compared with normal islets from control subjects, those of the VIPoma-associated pancreas showed a decrease of immunoreactive insulin in B-cells associated with cytological features indicative of enhanced insulin synthesis and secretion and an increase in the number of immunoreactive somatostatin- and pancreatic polypeptide-containing cells, in the absence of ultrastructural signs of modified secretory activity. No substantial alterations of A-cells were observed. In addition, images of diffuse de novo formation of ducts and islet tissue were often found. Possible mechanisms involved in determining the above changes are discussed.
Department of Human Anatomy and Histology, University of Florence, Italy.
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Bani Sacchi
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Bani
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Biliotti
D000328:Adult; D003594:Cytoplasmic Granules / Q000473:pathology; D005260:Female; D006056:Golgi Apparatus / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007328:Insulin / Q000378:metabolism*; D007515:Islets of Langerhans / Q000378:metabolism* / Q000648:ultrastructure*; D008297:Male; D008854:Microscopy, Electron; D008875:Middle Aged; D010183:Pancreatic Ducts / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000648:ultrastructure*; D010191:Pancreatic Polypeptide / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D003969:Vipoma / Q000648:ultrastructure*
D007328:Insulin; D013004:Somatostatin; D010191:Pancreatic Polypeptide