Derm Cases · Dermatology / Surgical oncology / Skin cancer MDT
OSCE — dual pathway skin cancer staging: melanoma biopsy/SLNB and high-risk cSCC risk stratification
An 8-minute OSCE on correct melanoma biopsy and AJCC T logic, SLNB/MSLT-II concepts, cSCC BWH high-risk features in an immunosuppressed patient, Mohs/H-zone thinking for NMSC, and when systemic therapy pathways apply.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE on correct melanoma biopsy and AJCC T logic, SLNB/MSLT-II concepts, cSCC BWH high-risk features in an immunosuppressed patient, Mohs/H-zone thinking for NMSC, and when systemic therapy pathways apply.
Brief (to candidate)
You are in a skin cancer clinic. Patient A has a changing pigmented back lesion (ABCDE positive). Patient B is a renal transplant recipient with a 2.8 cm ulcerated plaque on the ear. In 8 minutes, set out staging-focused plans for both without mixing pathways.
[1]Candidate instructions
- State correct biopsy for suspected melanoma vs acceptable diagnostic biopsy for NMSC.
- Explain AJCC 8 T drivers (Breslow, ulceration) and SLNB discussion threshold.
- Mention MSLT-II era approach if SLN positive.
- For ear cSCC in transplant: list high-risk / BWH features and nodal/MDT plan.
- Name one systemic option for advanced cSCC; note BCC is risk-stratified (Mohs for high-risk H-zone).
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Melanoma biopsy | Prefers full-thickness excisional biopsy with narrow margins; avoids incomplete superficial shave when melanoma likely[1] |
| AJCC T logic | Names Breslow thickness and ulceration as T drivers; can place a ≥0.8 mm or ulcerated thin lesion into T1b+ thinking for SLNB discussion[1] |
| SLNB / MSLT-II | Discusses SLNB for staging; if SLN+, observation with US may be alternative to routine completion dissection per MSLT-II principles[2] |
| cSCC risk | Flags size, site (ear), poor differentiation/ulceration, immunosuppression as high risk; BWH multi-factor upstaging → nodal exam ± imaging/MDT[3] |
| NMSC local therapy | High-risk H-zone/ear → specialist margin-controlled surgery/Mohs when available; not “observe” |
| Systemic awareness | Advanced cSCC: PD-1 (cemiplimab) pathway; localised BCC: risk strata / Mohs rather than full TNM for every papule[4][5] |
| Communication | Clear dual plan, urgency, UV protection, transplant team liaison for B |
Model key actions
- Lesion A: excisional biopsy → Breslow/ulceration → WLE ± SLNB discussion.[1]
- Lesion B: treat as high-risk cSCC in immunosuppressed host → MDT nodal risk pathway.[3]
- Do not apply melanoma margins/SLNB rules to BCC, or BCC “topical options” to thick melanoma.
Common errors
- Shave-only plan for obvious melanoma.
- Automatic CLND for every positive SLN without MSLT-II nuance.
- Calling all ear SCC “low risk” because “SCC is local.”
- Starting immunotherapy before histologic confirmation and staging context.
References5ShowHide
- [1]Gershenwald JE, Scolyer RA. Melanoma Staging: American Joint Committee on Cancer (AJCC) 8th Edition and Beyond. Annals of Surgical Oncology, 2018.PMID 29850954
- [2]Faries MB, Thompson JF, Cochran AJ, et al. Completion Dissection or Observation for Sentinel-Node Metastasis in Melanoma. New England Journal of Medicine, 2017.PMID 28591523
- [3]Cañueto J, Burguillo J, Moyano-Bueno D, et al. Comparing the eighth and the seventh editions of the American Joint Committee on Cancer staging system and the Brigham and Women's Hospital alternative staging system for cutaneous squamous cell carcinoma. Journal of the American Academy of Dermatology, 2019.PMID 30003984
- [4]Migden MR, Rischin D, Schmults CD, et al. PD-1 Blockade with Cemiplimab in Advanced Cutaneous Squamous-Cell Carcinoma. New England Journal of Medicine, 2018.PMID 29863979
- [5]Kim JYS, Kozlow JH, Mittal B, et al. Guidelines of care for the management of basal cell carcinoma. Journal of the American Academy of Dermatology, 2018.PMID 29331385