Derm Cases · Dermatology / Dermatopathology / Skin cancer
OSCE — keratinocytic pathology: AK–SCCIS–SCC spectrum, BCC subtype, report-to-action
An 8-minute OSCE on keratinocytic histopathology spectrum, adequate sampling, high-risk SCC features, BCC subtype implications, Ber-EP4 limits, and field cancerization counselling.
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Study tools
Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE on keratinocytic histopathology spectrum, adequate sampling, high-risk SCC features, BCC subtype implications, Ber-EP4 limits, and field cancerization counselling.
Brief (to candidate)
You are in a skin cancer clinic. A 70-year-old has sun-damaged skin with multiple AKs, a thick scalp lesion, and a nasal pearly nodule. The pathologist phones for clinical correlation. In 8 minutes, set out a safe clinicopathologic plan.
Candidate instructions
- Define AK vs SCCIS vs invasive SCC on histology.
- State how you would sample a thick lesion when invasion is possible.
- List high-risk SCC report items (depth, differentiation, PNI, margins).
- Explain BCC subtype impact (infiltrative → margin-critical/Mohs discussion).
- Mention Ber-EP4 as supportive with Bowen pitfall.
- Counsel field cancerization beyond a single AK.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Spectrum | Partial-thickness AK; full-thickness SCCIS; invasion defines invasive SCC |
| Sampling | Prefers adequate depth when invasive disease possible; flags superficial understaging |
| SCC risk | Names depth/PNI/differentiation/margins as actionable elements |
| BCC | Links infiltrative/micronodular subtype to careful margin control/Mohs framing |
| IHC | Ber-EP4 supports BCC vs SCC; not standalone; Bowen limitation |
| Field | Explains regional UV clonal field; lesion + field care concepts |
| Communication | Clear next steps without destroying undiagnosed lesions with cryo/laser |
Model key actions
- Architecture and invasion first; stains second.
- Do not dismiss incomplete deep margins on thick tumours.
- Map report language to surgery/MDT, not generic “skin cancer cream for all.”
References6ShowHide
- [1]Peris K, Fargnoli MC, Kaufmann R, et al. European consensus-based interdisciplinary guideline for diagnosis and treatment of basal cell carcinoma-update 2023. European Journal of Cancer, 2023.PMID 37604067
- [2]Wysong A. Squamous-Cell Carcinoma of the Skin. New England Journal of Medicine, 2023.PMID 37314707
- [3]Willenbrink TJ, Ruiz ES, Cornejo CM, et al. Field cancerization: Definition, epidemiology, risk factors, and outcomes. Journal of the American Academy of Dermatology, 2020.PMID 32387665
- [4]Tellechea O, Reis JP, Domingues JC, et al. Monoclonal antibody Ber EP4 distinguishes basal-cell carcinoma from squamous-cell carcinoma of the skin. American Journal of Dermatopathology, 1993.PMID 8238781
- [5]Kogut M, Toberer F, Enk AH, et al. Limitations of Ber-EP4 for distinction of Bowen disease from basal cell carcinoma. Journal of Cutaneous Pathology, 2016.PMID 26765054
- [6]Eisen DB, Asgari MM, Bennett DD, et al. Guidelines of care for the management of actinic keratosis: Executive summary. Journal of the American Academy of Dermatology, 2021.PMID 34111497