Endocrine pancreas

Pancreas
General
Endocrine pancreas

Author: Deepali Jain, M.D. (see Authors page)

Revised: 7 December 2017, last major update August 2012

Copyright: (c) 2002-2017, PathologyOutlines.com, Inc.

PubMed Search: Endocrine pancreas[TI] free full text[sb]

Table of Contents

Definition / general | Microscopic (histologic) images | Positive stains | Electron microscopy images

Cite this page: Jain, D. Endocrine pancreas. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/pancreasendocrine.html. Accessed June 19th, 2018.

Definition / general

Consists of islets of Langerhans, represents 1% of pancreas (percentage higher at birth)
Round, compact, highly vascularized with scanty connective tissue
More irregular outline and trabecular arrangement in posterior head of pancreas with cells producing pancreatic polypeptide
Size of islets usually 0.1 to 0.2 mm, endodermal origin, one million islets present in pancreas
Islet composition: beta cells (68%), alpha cells (20%), delta cells (10%), PP cells (2%), serotonin cells (rare)
Postgastrectomy, may get islet hypertrophy, then beta cell proliferation, then atrophy and amylin deposits (Hum Pathol 2000;31:1368)
Alpha cells: produce glucagon; peripherally dense and round on EM
Beta cells: produce insulin and islet cell amyloid polypeptide (amylin), crystalline appearance on EM with surrounding halo
Delta cells: produce somatostatin (represses release of insulin and glucagon), large pale granules on EM
D1 cells: produce vasoactive intestinal polypeptide (VIP), which induces glycogenolysis and hyperglycemia, stimulates GI fluid secretion and causes secretory diarrhea
Enterochromaffin cells: synthesize serotonin, produce carcinoid syndrome
Gastrin cells: pancreas usually lacks gastrin producing cells, although gastrinomas are common
PP cells: produce pancreatic polypeptide, which stimulates secretion of gastric and intestinal enzymes and inhibits intestinal motility; present in islets and scattered in exocrine pancreas; more PP cells in posterior head of pancreas (from ventral bud)
Nesidioblastosis: islets in intimate association with ducts with formation of ductuloinsular complexes
Nesidiodysplasia: loss of the usual centrilobular concentration of larger islets, with increased small irregularly distributed aggregates of islet cells; also increase in beta cell nuclear size and DNA content; may be associated with endocrine neoplasms (Hum Pathol 1988;19:1215)
Peliosis: selective congestion and dilation of vessels of islets only, not seen in vessels elsewhere