Small intestine & ampulla

Topic Completed: 1 December 2012

Minor changes: 1 September 2020

Copyright: 2003-2021,, Inc.

PubMed Search: Adenomyoma

Hanni Gulwani, M.B.B.S.
Page views in 2020: 1,266
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Cite this page: Gulwani H. Adenomyoma. website. Accessed May 8th, 2021.
Definition / general
  • Also called adenomyomatous hyperplasia
  • Rare, benign
  • Usually stomach, duodenum, jejunum
  • Often causes pain in right upper quadrant, radiating to back
  • May cause biliary obstruction and common bile duct dilation (Arch Pathol Lab Med 1987;111:388)
Case reports
  • Excision
Gross description
  • Mass at head of pancreas, usually 0.5 cm or more
Microscopic (histologic) description
  • Well circumscribed, nodular proliferation of smooth muscle cells, ducts and glands, clearly disorganized compared to normal
  • Ducts and glands are lined by columnar/cuboidal cells
  • No atypia, no mitoses, usually no pancreatic tissue
Positive stains
Negative stains
  • MUC1, MUC4
Differential diagnosis
  • Normal intraampullary common bile duct (normally has dense muscular layer)
  • Ectopic pancreatic tissue
  • Fibroadenoma
  • Brunner gland hyperplasia
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