Stomach
Polyps
Inflammatory fibroid polyp

Author: Naziheh Assarzadegan, M.D. (see Authors page)
Editor: Raul S. Gonzalez, M.D.

Revised: 9 August 2017, last major update August 2017

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

PubMed Search: Stomach (inflammatory fibroid polyp [title])
Cite this page: Assarzadega, N., Gonzalez, R.S. Inflammatory fibroid polyp. PathologyOutlines.com website. http://pathologyoutlines.com/topic/stomachinflammatoryfibroid.html. Accessed October 22nd, 2017.
Definition / general
  • Benign neoplastic polyp that occurs anywhere in gastrointestinal tract but most commonly in stomach and small intestine
Essential features
  • Benign mesenchymal gastrointestinal polyp that arises in the submucosa
  • Associated with PDGFRA mutation
Terminology
Sites
  • Usually arises in pylorus or distal antrum in stomach
Etiology
Clinical features
  • Peak incidence in 6th or 7th decade of life
  • No endoscopic surveillance is required after the histological diagnosis is confirmed
  • Rarely associated with adenocarcinoma or adenoma (Arch Pathol Lab Med 1988;112:829)
Case reports
Treatment
  • Local excision
Gross description
  • Typically solitary, small and sessile
  • Median size 1.5 cm but can measure up to 9 cm
Microscopic (histologic) description
  • Submucosal lersion composed of spindle and stellate stromal cells
  • Loose edematous stroma containing thin walled blood vessels with characteristic "onion skin" arrangement of spindled cells around vessels
  • Inflammatory infiltrate rich in eosinophils
  • Can infiltrate lamina propria
  • Minimal mitotic activity
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Naziheh Assarzadegan, M.D.

Low magnification

Intermediate magnification

High magnification



Case of the Week #421, contributed by 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

Positive stains
Negative stains
Molecular / cytogenetics description
  • Associated with activating mutation in the platelet derived growth factor receptor alpha (PDGFRA) gene, supporting a neoplastic origin (Histopathology 2012;61:59)
Differential diagnosis
Board review question #1
Which of the following statements is true about inflammatory fibroid polyps?

  1. They are associated with activating mutation in the platelet derived growth factor receptor alpha gene
  2. They are benign and nonneoplastic
  3. They are synonymous with inflammatory polyps
  4. They are typically centered on the muscularis propria
Board review answer #1
A. They are associated with activating mutation in the platelet derived growth factor receptor alpha gene