New vascular classification of port-wine stains: improving prediction of Sturge-Weber risk

Abstract

Background: Facial port-wine stains (PWSs) are usually isolated findings; however, when associated with cerebral and ocular vascular malformations they form part of the classical triad of Sturge-Weber syndrome (SWS).

Objectives: To evaluate the associations between the phenotype of facial PWS and the diagnosis of SWS in a cohort with a high rate of SWS.

Methods: Records were reviewed of all 192 children with a facial PWS seen in 2011-13. Adverse outcome measures were clinical (seizures, abnormal neurodevelopment, glaucoma) and radiological [abnormal magnetic resonance imaging (MRI)], modelled by multivariate logistic regression.

Results: The best predictor of adverse outcomes was a PWS involving any part of the forehead, delineated at its inferior border by a line joining the outer canthus of the eye to the top of the ear, and including the upper eyelid. This involves all three divisions of the trigeminal nerve, but corresponds well to the embryonic vascular development of the face. Bilateral distribution was not an independently significant phenotypic feature. Abnormal MRI was a better predictor of all clinical adverse outcome measures than PWS distribution; however, for practical reasons guidelines based on clinical phenotype are proposed.

Conclusions: Facial PWS distribution appears to follow the embryonic vasculature of the face, rather than the trigeminal nerve. We propose that children with a PWS on any part of the 'forehead' should have an urgent ophthalmology review and a brain MRI. A prospective study has been established to test the validity of these guidelines.

Fig 1

(a) Distribution of the three branches of the trigeminal nerve. (b) Distribution of the ‘forehead’, defined as any part of the forehead from the midline to an imaginary line between the outer canthus of the eye and the top of the ear including the upper eyelids. Figure adapted from Anatomy of the Human Body.

Fig 2

(a) Configuration of the facial placodes. The blue area represents the ‘forehead’, constituting a central frontonasal placode (marked by the dotted lines) and lateral optic vesicle areas. (b) Frontonasal prominence port-wine stain (PWS) – not to be confused with a salmon patch (naevus simplex). (c) PWS sparing the majority of the frontonasal prominence. (d) Unilateral PWS in the ‘forehead’, suggesting a mutation after division of vasculature into right and left.

Fig 3

Comparison of port-wine stain with the vascular and neural distribution, showing similarity to the vascular distribution in (a) the palm and (b) the sole. Figure adapted from Anatomy of the Human Body.

Fig 4

Great Ormond Street Hospital management guidelines for children with facial port-wine stain (PWS) on the forehead. MRI, magnetic resonance imaging.