early cardiac failure, recurrent spontaneous pneumothoraces, and progressive respiratory failure. Patients with TSC need lifelong follow-up for early detection of potentially life-threatening complications [164, 172].

7.5.4  Incidence

It is estimated that the incidence of SWS is one in 20–50,000 live births, although there is no good popu- lation-based data.

7.5  Sturge-Weber Syndrome

7.5.1  Introduction

SWS is a neurocutaneous disorder that presents with diffuse vascular malformation of the leptomeninges, choroid, and the facial skin. The other term for this disorder, encephalofacial hemangiomatosis emphasizes only the nonocular manifestations.

7.5.2  Historical Context

In 1879, William Sturge, an English physician, des­ cribed a syndrome characterized by a facial hemangioma, ipsilateral buphthalmos, and contralateral seizures [173]. In 1922, Frederick Weber, an English dermatologist, reported radiological evidence of cortical calcification secondary to leptomeningeal hemangioma causing hemiplegia. Since then, the triad of leptomeningeal, choroidal, and cutaneous hemangioma has been called SWS.

7.5.3  Overview with Clinical Significance

The most clinically evident presentation in patients with SWS is the facial cutaneous vascular malformation. However, it is important to note that most children with facial cutaneous angiomatosis do not have SWS.

Neurological manifestation of SWS is associated with significant morbidity and can cause intractable seizures, hemiparesis, hemianopsia, developmental delay, and behavioral problems. Ocular involvement with diffuse choroidal hemangioma and congenital glaucoma may result in visual loss from exudative retinal detachment and elevated intraocular pressure. Cutaneous manifestations of nevus flammeus are of diagnostic ­significance and cosmetic concern.

7.5.5  Genetics

Unlike other phakomatoses, SWS occurs sporadically.

7.5.6  Pathophysiology

SWS is thought to result from malformation of an embryonic vascular plexus within the cephalic mesenchyme between the neuroectoderm and the telencephalic vesicle. It is presumed that, at approximately 5–8 weeks of gestation, interference with the development of vascular drainage of these areas subsequently affects the face, eye, leptomeninges, and brain.

7.5.7  Natural History and Prognosis

SWS is a congenital disorder with the majority of findings evident at birth or in early childhood. However, the disease course is variable among patients. Developmental delay and behavior problems as a result of leptomeningeal involvement are more common in older children [174]. Diffuse choroidal hemangioma may not cause exudative retinal detachment until adolescence­ [175].

7.5.8  Signs and Symptoms

7.5.8.1  Diffuse Choroidal Hemangioma

Approximately, 50% of the patients with SWS have diffuse choroidal hemangioma [176]. Choroidal hemangioma in SWS appears as an orange colored diffuse choroidal thickening (Fig. 7.8). It is usually unilateral and ipsilateral to nevus flammeus although clinical variants have been reported [177]. The choroidal

Fig. 7.8  Diffuse choroidal hemangioma. Reproduced with permission from: Singh et al. [231]

hemangioma can lead to exudative retinal detachment. Treatment with low-dose standard radiotherapy or with proton beam is effective in inducing tumor regression and resolving subretinal fluid [178, 179].

7.5.8.2  Glaucoma

Glaucoma is the most frequent manifestation of SWS and occurs in about 70% of all cases [176]. The glaucoma is usually diagnosed within the first 2 years of life. The incidence of glaucoma is higher if the eyelids are involved with nevus flammeus [180]. Two mechanisms have been proposed for the development of glaucoma in SWS: (1) angle maldevelopment; (2) elevated episcleral venous pressure [181]. Although medical therapy is effective in some cases, the majority of patients require surgical treatment for glaucoma management [180, 182–184].

7.5.8.3  Nevus Flammeus

The cutaneous hemangioma is also called nevus flammeus or port-wine stain (Fig. 7.9). In general, only about 10% of all nevus flammeus cases are associated with SWS [175]. The likelihood of SWS increases when the cutaneous malformation involves the V1 or V2 distribution of the trigeminal nerve [175, 185]. Bilateral nevus flammeus have a higher likelihood of associated SWS than unilateral lesions. Conversely, leptomeningeal and ocular involvement of SWS is always associated with nevus flammeus of the eyelids, with the upper eyelid more often affected than the lower eyelid [175].

Fig. 7.9  A typical distribution of cutaneous hemangioma in Sturge–Weber syndrome. Reproduced with permission from: Singh et al. [231]

7.5.8.4  Leptomeningeal Hemangiomatosis

The leptomeningeal hemangiomatosis in SWS patients is ipsilateral to the cutaneous involvement and presents as a seizure disorder. Epilepsy develops in about 80% of patients and usually present by the age of 3 years [186]. The seizures are generally controlled with medications, but intractable cases require surgical resection of the leptomeningeal angiomatosis with the underlying cerebral cortex [187]. A correlation exists between the early onset of seizures and the likelihood of developmental delay and behavior problems [174, 188, 189]. Approximately, 50–60% of patients will have developmental delay or mental retardation [187, 188, 190, 191]. Transient focal neurologic deficits are a unique feature in SWS. The most common manifestations of these stroke-like episodes are hemiparesis (25–60%) and hemianopsia (40–45%). Other neurological complications include vascular headache (40–60%) and attention-deficit hyperactivity disorder [187, 188, 190, 191].

7.5.8.5  Diagnosis and Diagnostic Aids

Diffuse choroidal hemangioma is best detected using B-scan ultrasonography that typically demonstrates diffuse highly echogenic thickening of the choroid. Contrast-enhanced MRI is most suited for detecting cerebral atrophy and leptomeningeal angiomatos malformation [192]. If the MRI is normal, CT scan should be used to detect intracranial calcification.