Inflammatory fibroid polyp

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 12 April 2017, last major update August 2012

Copyright: (c) 2003-2017,, Inc.

PubMed Search: inflammatory fibroid polyp
Cite this page: Inflammatory fibroid polyp. website. Accessed June 24th, 2017.
Definition / general
  • Formerly called eosinophilic granuloma
  • Nonneoplastic / benign polyp that occurs anywhere in GI tract, but most common in stomach and small intestine
  • Usually 50 - 60 years old
  • Associated with achlorhydria, hypochlorhydria, pyloric obstruction
  • Usually antral
  • May occlude pyloric channel
  • Rarely associated with adenocarcinoma or adenoma (Arch Pathol Lab Med 1988;112:829)
Case reports
  • A 79 year old Chinese woman with chronic gastritis and a 2 cm sessile gastric polyp (Case of the week #421)
  • Local excision
Gross description
  • Sessile or pedunculated
  • Median size 1.5 cm, largest was 9 cm
Microscopic (histologic) description
  • Submucosal lesion with whorls of granulation tissue-like vessels, fibroblastic cells and prominent inflammatory response, primarily eosinophils
  • Also plasma cells and mast cells
  • Minimal mitotic activity
Microscopic (histologic) images
Images hosted on PathOut server, COW #421, courtesy of Dr. Leow Wei Qiang:

Polypoid mass expanding the submucosa

Mixed inflammatory infiltrate in fibromyxoid stroma, rich in eosinophils

Loose, fibromyxoid spindled stroma

CD34+ stromal cells with "onion skinning"

Stroma is CD117-,
with scattered CD117+
mast cells

Negative stains
  • CD117 (although mast cells are CD117+), S100