Cutaneous squamous cell carcinoma

Epidemiology

Etiology

Cumulative UV exposure (from the sun or from tanning beds) is the most significant risk factor

Pathophysiology

Clinical features

Precursor and early lesions Precursor lesions (actinic keratosis) and in situ lesions (Bowen disease) typically manifest as a enlarging, rounded nodule with rough (keratinized) surface ± ulceration, crusting and bleeding

Commonly on sun-exposed skin Pasted image 20240412214818.png

Pasted image 20240412214818.png

Invasive cSCC

Easy friability (i.e., bleeds easily after minor trauma)
Central ulceration
Typically occurs on sun-exposed areas

Metastatic cSCC

Most common sites for metastasis include lymph nodes (80%)

Diagnostics

Pathology

cSCC occurs as a result of malignant transformation of keratinocytes in the stratum spinosum (prickle cell layer) of the epidermis. These atypical keratinocytes appear as enlarged, polygonal cells with nuclear pleomorphism and atypical mitoses.

Sheets or nests of malignant keratinocytes
Keratinization (eg, keratin pearls) & intercellular bridges
- Keratin pearls: An abnormal structure formed by concentric layers of epithelial cells surrounding a keratin matrix secreted by the cells. Associated with well-differentiated squamous cell carcinoma.

Differential diagnostics

Feature	Basal Cell Carcinoma (BCC)	Cutaneous Squamous Cell Carcinoma (cSCC)
Origin	Basal cells in the epidermis	Squamous cells in the epidermis
Common Locations	Sun-exposed areas: face, neck	Sun-exposed areas: face, ears, neck, lips, back of the hands
Appearance	Pearly or waxy bump, flat flesh-colored or brown scar-like lesion	Firm, red nodule, flat lesion with a scaly, crusted surface
Growth Rate	Slow-growing	Can be faster-growing than BCC
Risk of Metastasis	Rare, low risk	Higher risk compared to BCC
Common Causes	Chronic sun exposure, fair skin	Chronic sun exposure, fair skin, history of burns or radiation exposure
Typical Age Group	Older adults	Older adults
Prevalence	Most common type of skin cancer	Second most common type of skin cancer
Treatment Options	Surgical removal, topical medications, radiation therapy	Surgical removal, topical medications, radiation therapy, chemotherapy for advanced cases
Prognosis	Generally good if detected early	Good if detected early; can be aggressive if untreated

Nodular BCC classically has a translucent or pearly appearance, often with central telangiectasias.
Cutaneous SCC classically has a rough or scaly (keratinized) surface

Treatment