Prostate gland & seminal vesicles
Benign lesions/conditions
Inflammatory pseudotumor

Topic Completed: 1 July 2012

Minor changes: 3 September 2020

Copyright: 2003-2020,, Inc.

PubMed search: prostatic inflammatory pseudotumor

Komal Arora, M.D.
Page views in 2019: 518
Page views in 2020 to date: 527
Cite this page: Arora K. Inflammatory pseudotumor. website. Accessed September 29th, 2020.
Definition / general
  • Also called pseudosarcomatous fibromyxoid tumor, inflammatory myofibroblastic tumor
  • Similar to postoperative spindle cell nodule but without history of TURP
  • Rare, resembles sarcoma or sarcomatoid carcinoma (Hum Pathol 1993;24:1203)
  • Diploid, low S phase fraction
  • Benign behavior
Case reports
Microscopic (histologic) description
  • Myxoid lesions, proliferation of slightly atypical spindle fibroblastic cells in a background of granulation tissue-type vascularity and inflammatory cells
  • Rare mitoses, no atypical mitoses
Positive stains
  • Vimentin, smooth muscle actin, CD68 (in histiocytes)
Negative stains
  • S100, desmin, myoglobin, keratin
Electron microscopy description
  • Fibroblastic and myofibroblastic cell features
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