## Diagnosis & Clinical Context **Key Point:** This is a well-differentiated squamous cell carcinoma (SCC) of the skin with low-risk features (small size <2 cm, well-defined borders, no perineural invasion mentioned, no nodal involvement). ## Management Approach for Cutaneous SCC ### Surgical Excision — Gold Standard Wide local excision (WLE) with adequate margins is the primary treatment for most cutaneous SCCs. The margin width depends on risk stratification: | Risk Category | Margin | Recurrence Rate | |---|---|---| | **Low-risk** (well-differentiated, <2 cm, no PNI) | 4–6 mm | <5% | | **Intermediate-risk** (mod. diff., 2–4 cm, or PNI) | 6–10 mm | 5–10% | | **High-risk** (poorly diff., >4 cm, deep invasion, PNI) | 10–15 mm or Mohs | >10% | **High-Yield:** Mohs micrographic surgery is reserved for: - High-risk anatomical sites (face, ear, lip, genitals) - Recurrent tumours - Poorly differentiated or deeply invasive lesions - Perineural invasion - Immunocompromised patients ### Why WLE with 4–6 mm margins is correct: 1. The lesion is **low-risk** (small, well-defined, actinic keratosis background typical of sun-exposed areas in farmers) 2. **Histology shows nests with keratinization** — consistent with well-differentiated SCC 3. **No nodal involvement** — no indication for lymph node dissection or sentinel lymph node biopsy 4. WLE is curative in >95% of low-risk cases **Clinical Pearl:** Always examine for perineural invasion (PNI) on histology — if present, upgrade to high-risk and consider Mohs or wider margins, as PNI predicts higher recurrence and worse prognosis. ## Post-Operative Follow-up - Clinical examination every 3–6 months for 2 years, then annually - Patient education on sun protection and surveillance for new lesions - Consider topical retinoids or field-directed therapy (5-FU, imiquimod) for actinic keratoses to reduce field cancerization risk [cite:Robbins 10e Ch 25] 
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