A 65-year-old man has a 2 cm lesion on the lower lip — a firm, indurated, non-healing ulcer with everted edges. Biopsy confirms well-differentiated squamous cell carcinoma. Which features of this SCC indicate HIGH risk of nodal metastasis requiring sentinel lymph node biopsy consideration?
- A Well-differentiated histology, <2 mm depth
- B Location on lip (high-risk anatomical site), depth >2 mm (Clark level IV), perineural invasion, diameter >2 cm ✓
- C History of prior actinic keratosis at the site
- D Positive margins on initial excision only
Correct answer: B. Location on lip (high-risk anatomical site), depth >2 mm (Clark level IV), perineural invasion, diameter >2 cm
Explanation
High-risk features for SCC metastasis include: anatomical site (lip, ear, non-sun-exposed areas), tumour diameter >2 cm, depth >2 mm or Clark level IV–V, poor differentiation, perineural or lymphovascular invasion, immunosuppression, and rapid growth. The lip is a high-risk site with 10–20% metastatic rate. These factors determine the need for wide local excision margins (>10 mm for high-risk), sentinel lymph node biopsy, and adjuvant radiotherapy. Low-risk SCC (trunk, well-differentiated, <2 mm depth) has <2% metastatic risk.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.