Squamous cell carcinoma of skin

Squamous cell carcinoma of skin 

Updated: 03/16/2021

© Jun Wang, MD, PhD

General features
  • Second most common skin cancer, after basal cell carcinoma
  • Commonly older population, men
  • Incidence associated with latitude
  • Higher risk in light skinned population
  • Usually NOT fatal
  • Excellent prognosis
  • Metastases uncommon
Risk factors
  • Exposure to natural and artificial ultraviolet light
  • Exposure to arsenic, tars and oils, ionizing radiations
  • Tobacco and betel nut chewing (oral cavity SCC)
  • Immunosuppression
  • HPV: Especially for SCC of anogenital or periungual sites; HPV 5/8 for patients with epidermodysplasia verruciformis
  • Certain skin disorders: light skin, actinic keratosis, xeroderma pigmentosum, epidermodysplasia verruciformis, albinism
Key pathogenesis
  • UV
UVB: most carcinogenic, absorbed by DNA
DNA damage and p53 mutation
Actinic keratosis
  • Also called solar keratosis, senile keratosis
  • Precancerous lesion on sun-exposed areas
  • May develop into squamous cell carcinoma or basal cell carcinoma
  • Biopsy needed to confirm diagnosis and rule out invasive SCC
Clinical features
  • Actinic keratosis
Small, rough spots
Cutaneous horn
  • Squamous cell carcinoma in situ (Bowen disease)
Rough, irregular, scaly patches
  • Invasive squamous cell carcinoma
Tumor, with or without ulceration
Key pathological features
  • Actinic keratosis
Atypia of basal layer keratinocytes
Disorderly maturation
Dermal elastosis
  • Squamous cell carcinoma in situ (Bowen disease)
Full thickness of keratinocytic atypia
Marked pleomorphism, mitosis beyond basal layer, etc
  • Invasive squamous cell carcinoma
Irregular cords or nests of atypical squamous cells
Intercellular bridges
Squamous pearl
Management
  • Electrodessication and curettage
  • Surgery
  • Radiation
  • Local or systemic chemotherapy



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