OSCE — pearly facial nodule: basal cell carcinoma recognition, risk stratification and treatment pathway

Brief (to candidate)

A 68-year-old fair-skinned man has a slowly enlarging pearly papule on the left nasal ala for 14 months with a rolled border, arborising telangiectases and central crusting. He has cumulative sun exposure and a prior scalp BCC. You have 8 minutes to recognise the lesion, stratify risk, plan diagnosis and outline management.

Candidate instructions

1. Describe nodular BCC morphology and key dermoscopy features.
2. Identify high-risk site/subtype factors (H-zone, ill-defined margins).
3. Plan appropriate biopsy and distinguish from SCC/melanoma mimics.
4. Outline surgical options (standard excision margins vs Mohs).
5. Mention non-surgical options for selected low-risk superficial BCC and Hedgehog inhibitors for advanced disease.
6. Give safety-net and photoprotection advice.

Examiner checklist (mark each domain / 10)

Model key actions

• Diagnose classic nodular BCC on the nasal ala using morphology ± dermoscopy.^[2][3]
• Flag H-zone high-risk site → prioritise Mohs discussion over casual observation.^[1]
• Plan tissue diagnosis then definitive margin-controlled treatment; discuss topical options only for appropriate superficial low-risk disease.^[1][4]
• Photoprotection, full skin examination, and follow-up for field UV damage.

Common errors

• Dismissing a pearly ulcerated nodule as "just a spot" without biopsy.
• Standard wide excision planning without recognising Mohs indications on the H-zone.
• Using radiotherapy as first choice in suspected Gorlin syndrome.
• Confusing pigmented BCC with melanoma and delaying appropriate biopsy pathway.
• Ignoring cumulative field damage and second primary skin cancers.