Prostate
Microscopic mimics of prostatic carcinoma
Squamous metaplasia

Author: Andres Matoso, M.D. (see Authors page)

Revised: 13 January 2016, last major update January 2016

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

PubMed Search: Squamous metaplasia [title] prostate
Definition / General
  • Squamous metaplasia is usually an incidental finding in the setting of infarction in the nodules of benign prostatic hyperplasia or secondary to treatment (hormonal therapy and radiation)
Essential Features
  • Usually incidental finding in the setting of inflammation, acute infarction of benign prostatic hyperplasia, or secondary to hormone / radiation therapy, or following prostatic artery embolization therapy for benign prostatic hyperplasia
  • Can present with cytologic atypia that is reactive to the underlying process
  • The key to avoid misinterpretation as cancer is to identify the underlying cause: i.e, adjacent hemorrhage or obvious necrosis indicating infarction, clinical history of hormone therapy or radiation
Epidemiology
  • It is more common to see in TURP specimens with infarct of nodules of benign prostatic hyperplasia
Pathophysiology
  • It is a reactive change of the prostatic epithelium
Etiology
  • Ischemia, hormone therapy, radiotherapy, inflammation
Clinical Features
  • Squamous metaplasia of the prostate is an incidental histologic finding without any clinical manifestations
  • No treatment is required
Micro Description
  • Nests of squamous epithelium whose cells have eosinophilic cytoplasm and focal keratinization
  • Mitoses can be seen but should not be frequent
Micro Images
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Needle biopsy

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Adjacent to infarction

Positive Stains
  • Squamous metaplasia is positive for the classic squamous markers including p63, CK5/6, HMWCK
Negative Stains
Differential Diagnosis