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Melanoma In Situ — SCE Dermatology MCQ

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EasySkin CancerMelanoma In SituSCE Dermatology

A 45-year-old man has a 15 mm diameter melanoma in situ on his back. He asks about the recurrence risk after adequate excision. What is the prognosis for melanoma in situ with complete excision?

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Correct answer: B — Excellent prognosis — 5-year survival approaches 100% with complete excision (no metastatic potential)

Melanoma in situ (Tis, stage 0), by definition, has not breached the basement membrane and therefore has no metastatic potential. Complete excision with histologically clear margins provides a cure rate approaching 100%. The 5-year melanoma-specific survival for melanoma in situ is 99-100%. However, the patient has an increased risk of developing a SECOND primary melanoma (3-5% lifetime) and requires ongoing skin surveillance. Lentigo maligna (melanoma in situ, lentigo maligna type) may have positive margins requiring staged excision due to subclinical extension, but once completely excised, prognosis is excellent. SLNB is not indicated for melanoma in situ.

Reference: BAD 2017 Melanoma Guidelines; AJCC 8th Edition