Mycosis Fungoides — SCE Dermatology MCQ

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ModerateSkin CancerMycosis FungoidesSCE Dermatology

A 60-year-old man with mycosis fungoides is being staged. He has patches and plaques covering 15% BSA with no lymph node or visceral involvement. Using the TNMB classification, what is his T stage?

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Correct answer: C — T2 (patches/plaques ≥10% BSA)

The TNMB staging system for mycosis fungoides/Sézary syndrome uses T staging based on skin involvement: T1 = patches/plaques covering <10% BSA (T1a patches only, T1b plaques ± patches); T2 = patches/plaques covering ≥10% BSA; T3 = one or more tumour nodules (≥1 cm); T4 = erythroderma (≥80% BSA). With 15% BSA of patches/plaques, this is T2. N staging assesses lymph node involvement, M staging visceral involvement, and B staging blood involvement (Sézary cells). Stage IA (T1N0M0B0) has excellent 10-year survival (>95%); stage IB-IIA (T2N0M0B0) has 10-year survival of approximately 70-80%.

Reference: BAD 2019 CTCL Guidelines; EORTC-ISCL TNMB