Squamous Cell Carcinoma (SCC) is a malignant tumour of keratinocytes arising from the epidermis.
It is the second most common skin cancer after basal cell carcinoma (BCC).
SCC is locally invasive and slower growing than melanoma, but unlike BCC it carries a real risk of metastasis.
Most often found on sun-exposed skin in older adults.

🌞 Causes / Risk Factors

UV radiation (sunlight or tanning beds) — cumulative lifelong exposure is the strongest factor.
Pre-malignant skin lesions: actinic keratosis, leukoplakia.
Chronic inflammation or scars (e.g. Marjolin’s ulcer in burns or ulcers).
Ionising radiation, tar, soot, oils, smoking, arsenic exposure.
Immunosuppression — organ transplant patients, HIV.
Increasing age due to cumulative DNA damage.

👀 Clinical Features

Non-healing ulcer or crusted, scaly nodule with a firm, indurated edge.
Most often on face, lips, ears, scalp, and hands.
May bleed, crust, or become painful.
Advanced disease → invasion of deeper tissue, perineural spread, or metastasis to lymph nodes.
High-risk SCC: lesions on lip/ear, diameter >2cm, depth >4mm, poorly differentiated histology, or in immunosuppressed patients.

Squamous Cell Carcinoma

Squamous Cell Carcinoma face

🧩 Bowen’s Disease

Bowen’s disease = SCC in situ (confined to the epidermis).
Presents as a scaly, erythematous plaque resembling psoriasis or eczema but persistent.
10–20% risk of progression to invasive SCC if untreated.

🧪 Investigations

Skin biopsy — diagnostic, showing atypical squamous cells invading dermis.
Lymph node assessment — FNA or biopsy if palpable.
Imaging (CT/MRI) — advanced or high-risk lesions.

💊 Management

Bowen’s disease:
- Curettage + cautery, cryotherapy, or photodynamic therapy.
- Topical 5-fluorouracil or imiquimod may be used.
Invasive SCC:
- Surgical excision with adequate margins (4–6 mm for low-risk, wider for high-risk).
- Mohs micrographic surgery — best for cosmetically sensitive or recurrent lesions (lips, eyelids, nose).
- Radiotherapy — option for inoperable cases or adjuvant in high-risk SCC.
Systemic therapy: Rare; immunotherapy (e.g., PD-1 inhibitors like cemiplimab) in metastatic/unresectable SCC.
Follow-up: Every 3–6 months initially, due to risk of recurrence and new primary tumours.

🔮 Prognosis

Early-detected SCC has an excellent prognosis.
5-year survival >90% if localised, but lower with nodal/distant spread.
High-risk lesions need closer surveillance and MDT input.

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