Sturg weber syndrome

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Sturge-Weber Syndrome (Encephalotrigeminal Angiomatosis)

Overview

Sturge-Weber syndrome (SWS) is a sporadic neurocutaneous disorder (phacomatosis) characterized by the triad of:

Facial port-wine nevus (capillary malformation)
Ipsilateral leptomeningeal angioma
Ocular abnormalities (particularly glaucoma)

It occurs in approximately 1 in 20,000 births and affects all races equally. It is not inherited - it is sporadic.

Etiology & Pathogenesis

SWS results from a somatic mosaic activating mutation in GNAQ (chromosome 9q21), with some cases also implicating GNA11. This mutation disrupts the q class of G-protein alpha subunits, reducing GTPase activity and increasing cell signaling. Because the mutation is somatic (not germline), it is not detectable on blood-based genetic testing - diagnosis rests on clinical findings.

Pathophysiologically, SWS results from persistence of the primitive embryonal vascular plexus that normally develops around the cephalic neural tube and facial skin during the 6th fetal week and regresses by the 9th week. When this regression fails, the persistent vascular plexus forms the characteristic angiomas.

Clinical Features

Cutaneous (Port-Wine Stain / Nevus Flammeus)

Port-wine stain in Sturge-Weber syndrome: adult with nodular thickened nevus (A) and child with periorbital involvement (B)

Two patients showing the classic port-wine nevus distribution. A: Nodular, thickened texture in an adult. B: Periorbital and episcleral involvement in a child - Bradley and Daroff's Neurology in Clinical Practice

Bilateral port-wine stain over forehead and periorbital region

Bilateral capillary malformation (port-wine stain) with Sturge-Weber syndrome - Andrews' Diseases of the Skin

The nevus involves the forehead and upper eyelid (V1/S1 distribution), may extend to lower face, trunk, and limbs
Present at birth; may thicken and develop nodular texture over time
Reactive hypertrophy of adjacent bone and connective tissue can occur
Only 10-20% of children with a forehead port-wine nevus have a leptomeningeal angioma
The more of the upper face involved, the higher the risk of intracranial involvement
Bilateral V1 or V1/V2/V3 involvement significantly increases the risk of SWS
Rarely, patients have the neurological/radiographic features of SWS without visible skin lesions

Neurological Features

Epilepsy, intellectual disability, and focal neurological deficits are the principal neurological abnormalities:

Feature	Details
Epilepsy	Develops in 72-80% of patients with unilateral lesions, 93% with bilateral involvement
Seizure onset	75% begin in the first year; 86% by age 2; 95% before age 5
Seizure types	Focal motor, generalized tonic-clonic; also infantile spasms, myoclonic, atonic
Intellectual disability	Develops in ~50% overall; only 8% with bilateral brain involvement are intellectually normal
Hemiparesis	Often acute at onset of seizures; may be permanent (stroke-like)
Hemianopia	Visual field deficits common due to frequent occipital lobe involvement

Early seizure onset (before age 2) is the strongest predictor of future intellectual disability and refractory epilepsy. Children with no seizures generally maintain normal intelligence. The condition eventually stabilizes, leaving residual deficits without further deterioration.

Ocular Features

Glaucoma is the main ophthalmological complication, with two age peaks: infancy and late childhood
Buphthalmos (enlarged globe) and amblyopia in some neonates
Choroidal angioma (diffuse, ipsilateral)
Episcleral hemangioma - causes blood in Schlemm's canal on gonioscopy
Iris heterochromia (ipsilateral to nevus)
Glaucoma can occur even without neurological involvement
Periodic intraocular pressure measurement is mandatory whenever the nevus is near the eye

Radiology / Imaging

CT Scan

CT head showing the classic occipital gyriform "tram-track" calcification pattern (arrow) - Bradley and Daroff's Neurology

Classic finding: "tram-track" or "tramline" calcifications following cortical gyri (calcium deposition in outer cortical layers)
CT detects calcification earlier than plain skull radiographs
Usually develops by age 2 years; almost never present in neonates
Calcifications result from abnormal venous drainage causing chronic cortical ischemia

MRI

MRI of Sturge-Weber Syndrome showing pial angioma, cortical atrophy, enlarged choroid plexus, and bilateral choroidal angiomas

Sturge-Weber syndrome MRI: (A) Coronal T1 post-contrast - enhancing pial angioma over right hemisphere with cortical atrophy and enlarged choroid plexus. (B) Axial T2 - prominent superficial and ependymal veins (arrows). (C) Axial post-contrast T1 - bilateral choroidal angiomas (arrows) - Grainger & Allison's Diagnostic Radiology

Gadolinium-enhanced MRI is the most sensitive investigation, especially in infancy before calcifications develop
Findings include: diffuse pial enhancement (leptomeningeal angioma), enlarged ipsilateral choroid plexus, dilated transparenchymal veins, and progressive hemispheric atrophy
T1 without contrast may appear completely normal early on
In "burnt-out" cases, the angioma may no longer enhance - only a shrunken, calcified hemisphere remains
MRI is preferred over CT in infancy; both are complementary
PET shows reduced glucose metabolism adjacent to the lesion (may show increased metabolism with recent seizures)
SPECT shows reduced perfusion, often revealing involvement beyond what CT shows

Classification (Roach Scale)

Type	Features
Type I	Facial AND leptomeningeal angioma (classic SWS); may have glaucoma
Type II	Facial angioma only; no intracranial involvement
Type III	Isolated leptomeningeal angioma; no facial nevus

Diagnosis

The diagnosis is clinical - the somatic mosaic GNAQ mutation is not detectable in peripheral blood. Neuroimaging is used to confirm intracranial involvement. MRI with gadolinium contrast is the preferred first investigation in an infant with a relevant port-wine stain.

Management

Seizures

Antiepileptic drugs (AEDs) are first-line; however, seizures are often refractory
Surgical options include focal cortical resection or hemispherectomy for refractory epilepsy - can improve seizure control and may promote better cognitive development
Patient selection criteria: refractory seizures + clinical dysfunction in the resection area + failure of adequate AED trial
Corpus callosotomy is used for refractory tonic or atonic seizures with extensive bilateral disease

Aspirin

Low-dose aspirin is offered to reduce stroke-like episodes, seizures, and cognitive impairment
Early institution may help prevent seizures and developmental delay (particularly in those confirmed to have SWS on imaging)
Generally well-tolerated; efficacy not definitively established by RCTs

Glaucoma

Requires periodic IOP monitoring from birth
Medical and/or surgical treatment for elevated IOP

Port-Wine Stain

Pulsed dye laser is the treatment of choice for lightening the nevus (ideally started early in infancy when lesions are more responsive)

Key Points to Remember

SWS is a phacomatosis (neurocutaneous syndrome), alongside NF1, NF2, tuberous sclerosis, and Von Hippel-Lindau
Caused by a somatic GNAQ mutation - sporadic, not inherited
The classic triad: port-wine stain (V1) + leptomeningeal angioma + glaucoma
Only 10-20% of upper facial port-wine stains have associated brain involvement
Leptomeningeal angioma is usually ipsilateral but bilateral brain lesions occur in at least 15%
MRI + gadolinium is the investigation of choice in infancy
The classic CT appearance is "tram-track" gyriform calcification in parieto-occipital cortex
Seizure onset before age 2 is the strongest predictor of intellectual disability
Bilateral brain involvement is associated with much worse cognitive outcomes (only 8% intellectually normal)

Sources: Bradley and Daroff's Neurology in Clinical Practice | Goldman-Cecil Medicine | Grainger & Allison's Diagnostic Radiology | Andrews' Diseases of the Skin | Kanski's Clinical Ophthalmology

Recent evidence note: A 2024 systematic review (PMID 39043228) examined headache as a feature of SWS, noting it is an underrecognized manifestation. A 2025 systematic review (PMID 40447045) highlighted that diffuse leptomeningeal melanomatosis can mimic Type III SWS and should be considered in the differential.

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