Skin - Nonmelanocytic tumors
Premalignant or noninvasive
Carcinoma in situ - general

Author: Christopher Hale, M.D. (see Authors page)

Revised: 13 October 2016, last major update June 2012

Copyright: (c) 2002-2016,, Inc.

PubMed Search: Carcinoma in situ [title] skin

Cite this page: Carcinoma in situ - general. website. Accessed October 27th, 2016.
Definition / General
  • Controversial topic: typical progression from mild to moderate to severe dysplasia to invasion seen in cervix may not apply to skin
  • Actinic keratosis with only a single layer of atypical keratinocytes may be invasive, but Bowen’s 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
  • Rough, irregular, scaly patches
Micro Description
  • By definition requires full thickness keratinocyte atypia, although may be surrounded by normal keratinocytes
  • Marked nuclear and architectural atypia, numerous mitotic figures, atypical mitotic figures, apoptotic cells
  • Variable melanin, variable lymphocytic infiltrate
  • May have hemangiomatous vascular proliferation, amyloid globules, adnexal differentiation
Micro Images

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Actinic keratosis (AK)

Squamous cell carcinoma in situ / Bowen's disease

Differential Diagnosis