Derm Cases · Dermatology / Paediatrics
OSCE — neonatal blue-grey sacral patch
OSCE: diagnose CDM, counsel natural history, document, handle bruise/safeguarding question, mention extrasacral red flags.
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Study tools
Target exams
NEET-PGINICETPLABMRCP
Prompt
OSCE: diagnose CDM, counsel natural history, document, handle bruise/safeguarding question, mention extrasacral red flags.
Brief (to candidate)
Parents of a day-2 neonate are worried about a blue patch on the baby’s lower back. Explain the diagnosis, natural history, what you will document, and answer a question about bruises/abuse.
[8]Candidate instructions
- Name the lesion using modern + exam terminology.
- Explain why it looks blue.
- Natural history.
- Documentation plan.
- Bruise/safeguarding reasoning.
- When you would not simply reassure.
Examiner checklist
| Domain | Key actions expected |
|---|---|
| Diagnosis | Congenital dermal melanocytosis / Mongolian spot[1] |
| Mechanism | Dermal melanocytes; optical depth/blue-grey colour |
| Course | Usually fades through childhood |
| Documentation | Site, size, photo, birth presence |
| Safeguarding | Birth-present stable lesion vs evolving bruise; whole-context approach[7] |
| Red flag | Extensive extrasacral + systemic clues → further evaluation[2] |
Model key actions
- Reassure classic sacral CDM; document carefully.[1]
- Handle abuse question thoughtfully using timeline logic.[7]
- Mention when extensive disease needs more than reassurance.[2]
Common errors
- Ordering unnecessary biopsy.
- Dogmatic “never abuse” or “always abuse” without reasoning.
- Failing to document.
References4ShowHide
- [1]Gupta D, Thappa DM. Mongolian spots. IJDVL, 2013.PMID 23760316
- [2]Hanson M, et al. Dermal melanocytosis and storage disease. Arch Dermatol, 2003.PMID 12873889
- [7]Rzepczyk S, et al. The so-called Mongolian spots and suspected child abuse - difficulties in differential diagnosis. Arch Med Sadowej Kryminol, 2024.PMID 40366721
- [8]Zhu J, Cen Q, Chang R, et al. Patchy Dermal Melanocytosis: Differential Diagnosis and Management J Cosmet Dermatol, 2025.PMID 39485055