Prostate gland & seminal vesicles

Benign mimickers of carcinoma

Squamous metaplasia

Topic Completed: 1 January 2016

Minor changes: 4 September 2020

Copyright: 2003-2020,, Inc.

PubMed Search: Squamous metaplasia [title] prostate

Andres Matoso, M.D.
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Cite this page: Matoso A. Squamous metaplasia. website. Accessed December 3rd, 2021.
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
  • It is more common to see in TURP specimens with infarct of nodules of benign prostatic hyperplasia
  • It is a reactive change of the prostatic epithelium
  • 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
Microscopic (histologic) description
  • Nests of squamous epithelium whose cells have eosinophilic cytoplasm and focal keratinization
  • Mitoses can be seen but should not be frequent
Positive stains
  • Squamous metaplasia is positive for the classic squamous markers including p63, CK5/6, HMWCK
Negative stains
Differential diagnosis
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