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Skin - Nonmelanocytic tumors

Premalignant or noninvasive

Carcinoma in situ-general

Reviewer: Christopher Hale, M.D. (see Reviewers page)
Revised: 4 July 2012, last major update June 2012
Copyright: (c) 2001-2012, PathologyOutlines.com, Inc.


● 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

● 78 year old male with multifocal persistent lesions of glans (J Dtsch Dermatol Ges 2006;4:559)

Clinical images

Squamous cell carcinoma in situ - various images

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

Actinic keratosis (AK)

Squamous cell carcinoma in situ / Bowen's disease

Differential diagnosis

● Actinic keratosis
● Arsenical keratosis
● Bowen’s disease
● Superficially invasive squamous cell carcioma

End of Skin - Nonmelanocytic tumors > Premalignant or noninvasive > Carcinoma in situ-general

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