Port-wine birthmark — SAQ

Questions

a) State the diagnosis and classify it using current vascular-anomaly terminology. Give its expected cutaneous course. (3 marks) [3]

b) Explain why this facial distribution matters. State the two specialist referral pathways and the family safety-net. (4 marks) [12][14]

c) Does this well infant automatically require neonatal MRI? Give an evidence-bounded imaging answer, including the limitation of an early negative scan. (3 marks) [12]

d) Give one discriminator from naevus simplex and one from infantile haemangioma. Avoid an unsafe absolute statement about infantile haemangioma at birth. (2 marks) [3][15]

e) Outline first-line treatment and counsel on response, safety, analgesia/anaesthesia, and inheritance. (3 marks) [6][13]

Model Answer

a) Diagnosis, classification, and natural history — 3 marks

• Diagnosis: port-wine birthmark (port-wine stain; naevus flammeus).
• Classification: a congenital capillary malformation within the ISSVA vascular-malformation group; it is not a vascular tumour.
• Course: present at birth, grows with the child, persists rather than involutes, and may darken, thicken, become nodular, or develop soft-tissue overgrowth. Progression and timing vary. [3][15]

b) Distribution, referrals, and safety-net — 4 marks

Award one mark for each: [12]

1. Forehead involvement predicts the Sturge-Weber brain-risk pathway better than describing the lesion as a V1 trigeminal dermatome. Arrange baseline paediatric neurology assessment and periodic specialist follow-up. [12][14]
2. Any upper- or lower-eyelid/periocular involvement predicts glaucoma risk. Arrange prompt paediatric ophthalmology assessment with intraocular-pressure and full ocular examination; follow-up is lifelong and individualized. [12][15]
3. Explain that SWS can be incomplete; do not require a complete “PWB + leptomeningeal angioma + glaucoma” triad before referral. [12]
4. Safety-net for a first seizure, focal weakness, stroke-like episode, developmental regression, photophobia, tearing, corneal clouding, or apparent eye enlargement. [12]

c) MRI in the asymptomatic infant — 3 marks

• No universal automatic neonatal MRI rule: routine screening MRI is not recommended for every asymptomatic high-risk infant. The paediatric neurologist discusses selective imaging, especially for extensive/bilateral disease, subtle symptoms, or when presymptomatic therapy is contemplated. [12]
• If selective asymptomatic imaging is chosen, an expert centre may use a fast, non-sedated protocol with susceptibility-sensitive sequences. If symptoms develop, use an optimized symptom-directed MRI protocol with appropriate pre- and post-contrast sequences. [12]
• An early normal MRI does not exclude SWS. Continue neurology follow-up and the seizure/developmental safety-net rather than falsely reassuring the family. [12]

d) Differential diagnosis — 2 marks

• Naevus simplex: often central or symmetric at the glabella, eyelids, or nape and usually fades; a nuchal stain may persist. Blanching alone is not an absolute separator. [3][15]
• Infantile haemangioma: a vascular tumour that proliferates in the first weeks and later involutes. A subtle precursor may be visible at birth, so “visible at birth cannot be haemangioma” is unsafe. [15]

e) Treatment and counselling — 3 marks

• First-line treatment, if wanted: pulsed dye laser. It uses selective photothermolysis; earlier treatment may help, but there is no universal starting age, parameter set, session interval, number of sessions, or clearance percentage. Expect multiple sessions, variable lightening, uncommon complete clearance, and possible touch-ups. [13]
• Safety and comfort: individualize settings and endpoint to lesion and phototype and use epidermal cooling. Treatment within the orbital rim requires properly fitted corneo-scleral shields; treatment outside the orbital rim requires laser-wavelength-specific external eye shields. Discuss pain, oedema, purpura, pigment change, and rare blistering or scarring. Analgesia and general anaesthesia are case-by-case shared decisions rather than an infant standard. [13]
• Inheritance: mosaic GNAQ p.R183Q is common but not universal. PWB is usually sporadic; recurrence for siblings or future children is expected to be low, not promised as zero. [6]

Examiner Notes

A full-mark answer must separate the neurology, ophthalmology, and specialist-led MRI decisions. Deduct marks for “V1 mandates neonatal contrast MRI,” “V2/V3 means zero risk,” a fixed laser recipe, “all infantile haemangiomas are absent at birth,” or “recurrence risk is exactly zero.” [12][13][14][15]