Derm Cases · Dermatology / Paediatrics / Neurology / Ophthalmology
OSCE — facial port-wine stain: capillary malformation, PDL, and Sturge-Weber screen
An 8-minute OSCE station on port-wine stain as a capillary malformation (not a tumour), GNAQ mosaicism, pulsed-dye laser principles, and mandatory Sturge-Weber screening for V1 distribution.
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Target exams
NEET-PGINICETUSMLEPLABMRCP
Prompt
An 8-minute OSCE station on port-wine stain as a capillary malformation (not a tumour), GNAQ mosaicism, pulsed-dye laser principles, and mandatory Sturge-Weber screening for V1 distribution.
Brief (to candidate)
A neonate has a unilateral pink-red facial patch in a V1 forehead/upper eyelid distribution present at birth. Parents ask if it is a "strawberry birthmark that will go away" and whether laser is needed. You have 8 minutes to reclassify, screen for Sturge-Weber, and plan care.
[1]Candidate instructions
- Define PWS as a capillary malformation, not infantile haemangioma.
- State natural history (grows with child, darkens/thickens, does not involute).
- Link GNAQ mosaicism conceptually.
- Screen Sturge-Weber for V1 involvement.
- Outline pulsed-dye laser role and timing discussion.
Examiner checklist (mark each domain / 10)
| Domain | Key actions expected |
|---|---|
| Classification | Congenital capillary malformation (ectatic dermal vessels); not a vascular tumour; present at birth and proportional growth — contrasts with proliferating infantile haemangioma that often involutes later[3] |
| Genetics | Somatic mosaic GNAQ R183Q (shared with SWS) — not germline Mendelian inheritance for isolated PWS typically[6] |
| Natural history | Does not involute; darkens to purple, may thicken/nodulate in adulthood; early laser may reduce hypertrophy risk |
| Sturge-Weber screen | V1 (forehead/upper eyelid) ± seizures/glaucoma risk → ophthalmology (glaucoma) and neuroimaging (MRI brain with contrast) pathway; counsel seizures/neurodevelopmental risk when SWS present[1][4][5] |
| Other associations | Limb PWS + overgrowth/varicosities → consider Klippel-Trenaunay; adult nodularity/bleeding may need lesion-directed care |
| Treatment | Pulsed-dye laser (PDL) first-line for lightening; multiple sessions; earlier treatment often preferred; set expectations (improvement not always complete erasure) |
| Communication | Correct "it will go away like a haemangioma" myth; arrange eye review urgently if V1 |
Model key actions
- Reclassify as PWS/capillary malformation that will not involute.[3]
- For V1 facial PWS, arrange ophthalmology + brain MRI for Sturge-Weber risk.[1][5]
- Offer PDL pathway with realistic expectations.
Common errors
- Calling PWS infantile haemangioma and watching for involution only.
- Missing glaucoma screen for periocular V1 lesions.
- No SWS discussion for forehead/eyelid distribution.
- Promising single-session complete clearance with laser.
References5ShowHide
- [1]Higueros E, Roe E, Granell E, et al. Sturge-Weber Syndrome: A Review. Actas dermo-sifiliograficas, 2017.PMID 28126187
- [3]Escobar K, Pandher K, Jahnke MN. Capillary Malformations. Dermatologic Clinics, 2022.PMID 36243429
- [4]Sánchez-Espino LF, Ivars M, Antoñanzas J, et al. Sturge-Weber Syndrome: A Review of Pathophysiology, Genetics, Clinical Features, and Treatment. The application of clinical genetics, 2023.PMID 37124240
- [5]Yeom S, Comi AM. Updates on Sturge-Weber Syndrome. Stroke, 2022.PMID 36263782
- [6]Shirley MD, Tang H, Gallione CJ, et al. Sturge-Weber syndrome and port-wine stains caused by somatic mutation in GNAQ. New England Journal of Medicine, 2013.PMID 23656586