Nodular Lesion on the Ear: When to Use Ancillary Testing
A 70-year-old man has a 0.9 cm pearly nodule on the helical rim with telangiectasia. Punch biopsy shows basaloid islands with peripheral palisading and clefting, consistent with nodular basal cell carcinoma. The lesion is close to the cartilage and the margin is 0.2 mm from the deep aspect. The surgeon asks whether Mohs surgery is indicated and whether immunohistochemistry is needed to confirm clearance.
1. Is immunohistochemistry needed to confirm clearance in this case, and why or why not?
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No. Nodular basal cell carcinoma with typical palisading and clefting is diagnosable on H&E, and routine immunohistochemistry (e.g., Ber-EP4) is not required to confirm clearance. Ber-EP4 can help distinguish BCC from squamous or adnexal mimics in ambiguous cases but is not a substitute for careful margin evaluation. The more important issue is that a 0.2 mm deep margin near cartilage indicates a high-risk anatomic site and close margin, which supports Mohs micrographic surgery or re-excision with margin control rather than relying on a stain.
2. What features make this a high-risk basal cell carcinoma, and how does that affect management?
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High-risk features include location on the ear (embryonic fusion plane), a close deep margin (0.2 mm), and proximity to cartilage. These favor Mohs surgery, which provides complete margin assessment and tissue conservation. The pathology report should state the margin distance and the high-risk location so the surgeon can justify Mohs. If Mohs is unavailable, re-excision with controlled margins is appropriate.
3. If the lesion recurred after prior excision, how would that change your approach?
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Recurrence is an additional high-risk feature and strengthens the indication for Mohs surgery, because recurrent tumors have unpredictable subclinical extension and higher failure rates with conventional excision. The pathologist should note the prior excision and any scarring, and the surgeon should plan Mohs with mapping. Ancillary stains remain optional, not required.