Neuroimaging findings of Sturge-Weber Syndrome in a child with Tuberous Sclerosis

Current concepts on ocular vascular abnormalities in the phakomatoses

BACKGROUND

Neurofibromatosis, Von Hippel Lindau disease, and tuberous sclerosis complex are classified under the term phakomatoses. They are characterized by ocular vascular abnormalities such as vascular tortuosity, corkscrew retinal vessel configuration, moyamoya-like aspect, microaneurysms, hemangioblastomas, and focal sheathing of retinal arteries, possibly due to abnormal formation, migration, and differentiation of neural crest cells. These alterations can be the first sign or the hallmark of disease and can be related to vasoproliferative tumors.

PURPOSE

Novel imaging technologies in ophthalmology, such as near-infrared reflectances and spectral domain optical coherence tomography, have improved our knowledge in the diagnosis of these pathologies. Previously undetected macular vascular alterations have been reported in phakomatoses using optical coherence tomography angiography. This review will summarize the ophthalmic vascular abnormalities and novel imaging methods in the phakomatoses.

CONCLUSION

Active research is being led into the ophthalmic management of these conditions and their complications, and owing to elevated vascular endothelial growth factor production from hemangioblastoma, hamartoma, and retinal vascular proliferative tumors, increasing interest in this line of therapy has been conducted although research is still ongoing in this area.

Epilepsy Mechanisms in Neurocutaneous Disorders: Tuberous Sclerosis Complex, Neurofibromatosis Type 1, and Sturge-Weber Syndrome

Neurocutaneous disorders are multisystem diseases affecting skin, brain, and other organs. Epilepsy is very common in the neurocutaneous disorders, affecting up to 90% of patients with tuberous sclerosis complex (TSC) and Sturge–Weber syndrome (SWS), for example. The mechanisms underlying the increased predisposition to brain hyperexcitability differ between disorders, yet some molecular pathways overlap. For instance, the mechanistic target of rapamycin (mTOR) signaling cascade plays a central role in seizures and epileptogenesis in numerous acquired and genetic disorders, including several neurocutaneous disorders. Potential routes for target-specific treatments are emerging as the genetic and molecular pathways involved in neurocutaneous disorders become increasingly understood. This review explores the clinical features and mechanisms of epilepsy in three common neurocutaneous disorders—TSC, neurofibromatosis type 1, and SWS.

Sturge Weber-Like Gyral Calcification Seen in Tuberous Sclerosis Complex 1

A 10-year-old girl presented with poorly controlled epilepsy. On evaluation, she had microcephaly, neuro-cutaneous stigmata of tuberous sclerosis complex, profound mental retardation, and spastic hemiparesis. Computed tomography (CT) revealed a calcified subependymal nodule and extensive left gyral calcification of the temporal, parietal, and occipital regions with unilateral cerebral atrophy, radiologic features usually seen in Sturge Weber syndrome. Magnetic resonance imaging (MRI) revealed absence of tubers, enlarged choroid plexus, or leptomeningeal angiomas, thus excluding type 3 Sturge Weber syndrome. The genotype was a heterozygous mutation in exon 18 of the tuberous sclerosis type 1 gene (c.2293C>T p.Q765X). A comparison of previously reported 7 cases of Sturge Weber syndrome and tuberous sclerosis complex was made. This revealed 4 actual double phakomatoses (clinical, radiologic, or genetic phenotypes) and 3 cases with clinical phenotype of tuberous sclerosis and gyral calcifications within tubers simulating the radiologic picture of Sturge Weber syndrome.

Tuberous sclerosis

Tuberous sclerosis complex (TSC) is a genetic multisystem disorder characterized by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver. The affected genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian-target-of-Rapamycin (mTOR) pathway, which controls cell growth and proliferation. Variations in the distribution, number, size, and location of lesions cause the clinical syndrome to vary even between relatives. About 85% of children and adolescents with TSC have CNS complications, including epilepsy, cognitive impairment, challenging behavioral problems, and autism-like symptoms. Epilepsy generally begins during the first year of life, with focal seizures and spasms. The discovery of the mTOR pathway upregulation in TSC-associated lesions presents new possibilities for treatment strategy. Increasing understanding of the molecular abnormalities caused by TSC may enable improved management of the disease.