Skin nonmelanocytic tumor
Premalignant or noninvasive
Squamous cell carcinoma in situ / Bowen disease


Topic Completed: 1 June 2012

Revised: 11 April 2019

Copyright: 2002-2019, PathologyOutlines.com, Inc.

PubMed Search: Carcinoma in situ [title] skin

Christopher S. Hale, M.D.
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Cite this page: Hale CS. Squamous cell carcinoma in situ / Bowen disease. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/skintumornonmelanocyticcisgeneral.html. Accessed October 14th, 2019.
Definition / general
  • Usually on skin NOT exposed to sunlight, such as trunk
  • Called erythroplasia (of Queyrat) if at glans penis, vulva, oral cavity
  • Actinic keratosis with only a single layer of atypical keratinocytes may be invasive but Bowen disease seldom is
  • Mucosal variants in glans penis (penile intraepithelial neoplasia or "PIN") and vulva (vulvar intraepithelial neoplasia or "VIN") are associated with more aggressive behavior
Case reports
Gross description
  • Slightly raised, large scaly erythematous plaque with irregular border
  • Usually single patch or verrucous growth
Microscopic (histologic) description
  • By definition requires full thickness keratinocyte atypia, although may be surrounded by normal keratinocytes
  • Architectural and cellular atypia, apoptotic cells, individual cell dyskeratosis
  • Markedly altered maturation but usually still some surface keratinization and intercellular bridges present
  • Marked nuclear atypia, including nuclear hyperchromasia and multinucleation
  • Numerous mitotic figures, atypical mitotic figures
  • Also cytoplasmic vacuoles; rarely pagetoid cells or ground glass cytoplasm
  • May extend into eccrine sweat glands (not considered invasive disease)
  • Variable melanin, variable lymphocytic infiltrate
  • May have hemangiomatous vascular proliferation, amyloid globules, adnexal differentiation
Microscopic (histologic) images

Contributed by Dr. Amy Lynn



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Various images

Differential diagnosis
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