Derm Cases · Dermatology / Surgical Oncology
OSCE — changing pigmented lesion: melanoma recognition, biopsy and staging pathway
An 8-minute OSCE station on ABCDE/ugly-duckling assessment, dermoscopy concepts, correct biopsy technique, Breslow-based staging principles, and urgent referral pathway for suspected cutaneous melanoma.
On this page
Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on ABCDE/ugly-duckling assessment, dermoscopy concepts, correct biopsy technique, Breslow-based staging principles, and urgent referral pathway for suspected cutaneous melanoma.
Brief (to candidate)
A 52-year-old fair-skinned man noticed a changing brown–black lesion on his upper back over 4 months. It is asymmetric with irregular border and colour variegation; a smaller regular naevus nearby looks different. He has a history of blistering sunburns. You have 8 minutes to assess risk, plan biopsy, and outline staging and next steps.
Candidate instructions
- Apply ABCDE and ugly-duckling rules; mention dermoscopy red flags.
- State the correct biopsy method (and what not to do).
- Explain Breslow thickness, ulceration, and AJCC staging concepts.
- Outline wide local excision margins concept and when sentinel lymph node biopsy is considered.
- Mention BRAF / immunotherapy relevance at high level for advanced disease.
- Give clear urgency and safety-net.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Recognition | Suspects melanoma: Asymmetry, Border irregularity, Colour variegation, Diameter/evolution, Evolving; ugly-duckling vs neighbouring naevi[1][2] |
| Dermoscopy concepts | Chaos and clues / atypical network, blue-white structures, irregular dots/globules — refers for dermoscopic assessment rather than observing indefinitely[3] |
| Biopsy technique | Full-thickness excisional biopsy with narrow margins preferred; avoid partial superficial shave that may understage Breslow when avoidable |
| Histopathology / staging | Key prognostic features: Breslow depth, ulceration, mitotic rate; AJCC 8th T by thickness/ulceration; N for nodal burden including SLNB pathway[1] |
| Surgical pathway | After confirmation: wide local excision with depth-based margins; discuss SLNB for appropriate Breslow thresholds; multidisciplinary team |
| Advanced disease brief | Notes BRAF V600 (~50%) for targeted therapy eligibility; checkpoint immunotherapy for unresectable/metastatic disease in specialist care[4] |
| Communication | Urgent dermatology/plastics pathway; sun-protection counselling; full skin and nodal exam; do not delay with prolonged observation |
Model key actions
- Flag changing pigmented lesion meeting ABCDE/ugly-duckling as suspected melanoma — urgent specialist pathway.[2]
- Plan excisional biopsy for definitive Breslow staging, then WLE ± SLNB per thickness.[1]
- Mention BRAF testing and systemic options only after staging in advanced disease.[4]
Common errors
- Watchful waiting of an evolving ABCDE lesion.
- Shave biopsy only that risks incomplete Breslow assessment.
- Focusing only on diameter while ignoring evolution / ugly duckling.
- Jumping to systemic therapy without histologic confirmation and staging.
- Missing total skin and nodal examination.
References4ShowHide
- [1]Tasdogan A, Sullivan RJ, Katalinic A, et al. Cutaneous melanoma. Nature Reviews Disease Primers, 2025.PMID 40180935
- [2]Joshi UM, Kashani-Sabet M, Kirkwood JM. Cutaneous Melanoma: A Review. JAMA, 2025.PMID 40853557
- [3]Marghoob NG, Liopyris K, Jaimes N. Dermoscopy: A Review of the Structures That Facilitate Melanoma Detection. The Journal of the American Osteopathic Association, 2019.PMID 31135866
- [4]Castellani G, Buccarelli M, Arasi MB, et al. BRAF Mutations in Melanoma: Biological Aspects, Therapeutic Implications, and Circulating Biomarkers. Cancers, 2023.PMID 37627054