Ampulla of Vater

Author: Hanni Gulwani, M.D. (see Authors page)

Revised: 22 January 2016, last major update December 2012

Copyright: (c) 2003-2016,, Inc.

PubMed Search: Adenomyoma
Cite this page: Adenomyoma. website. Accessed October 16th, 2018.
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
Microscopic (histologic) images

Benign ducts with whorled smooth muscle stroma

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