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Basal Cell Carcinoma — SCE Dermatology MCQ

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HardDermatological SurgeryBasal Cell CarcinomaSCE Dermatology

Biopsy of a poorly demarcated nasal plaque shows morphoeic basal cell carcinoma with narrow cords of basaloid cells in sclerotic stroma. Which feature most strongly supports Mohs micrographic surgery?

Educational content. Not a substitute for clinical judgement or local policy.

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Correct answer: B — Complete mapped peripheral and deep margin examination can track asymmetric subclinical extensions

Explanation lettering: E = shown as C · C = shown as E

B is correct. Morphoeic BCC is high risk because clinically occult, asymmetric strands extend through fibrotic dermis. Mohs examines the complete mapped peripheral and deep margin and removes further tissue only where tumour remains, combining clearance with tissue conservation on the nose. Vertical bread-loaf sections sample rather than examine the entire margin. A fixed 3 mm margin is unreliable for an infiltrative subtype, curettage does not alter tumour biology, and Mohs is not cosmetic-subunit excision. The histological growth pattern, site and ill-defined border collectively support margin-controlled surgery.

Reference: BAD basal cell carcinoma guidance: https://www.bad.org.uk/pils/basal-cell-carcinoma