Neurocutaneous Syndromes
Neurocutaneous syndromes, or phakomatoses, are disorders characterized by the presence of hamartomas involving different organ systems, such as the skin, eyes, CNS, and viscera. Phakomatoses are inconsistently defined, and there is a lack of consensus about which conditions should be considered neurocutaneous syndromes. Four major disorders have traditionally been designated phakomatoses:
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neurofibromatosis type 1 (von Recklinghausen disease, Fig 14-6) and type 2
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tuberous sclerosis (Bourneville disease, Fig 14-7)
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angiomatosis of the retina and cerebellum (von Hippel–Lindau disease, Fig 14-8)
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ataxia-telangiectasia (Louis-Bar syndrome, Fig 14-9)
Encephalofacial angiomatosis (Sturge-Weber syndrome, Fig 14-10), racemose angioma (Wyburn-Mason syndrome, Fig 14-11), incontinentia pigmenti, and Klippel-Trénaunay-Weber syndrome are among the other conditions sometimes classified as phakomatoses.
These disorders, which are discussed at length in BCSC Section 6, Pediatric Ophthalmology and Strabismus, are characterized by tumors formed from normal tissue elements: hamartomas and choristomas. A hamartoma is composed of elements normally found at the involved site; hamartomas are not true neoplasms, because they are anomalies of tissue formation that lack the capability for limitless proliferation. The glial retinal tumors of tuberous sclerosis are a type of hamartoma. Choristomas are tumor-like growths composed of tissue not normally present at the site of growth. Some phakomatous lesions are neoplasms, but the majority are hamartomas or choristomas.
Table 14-2 summarizes the important features of the most common phakomatoses.
Ullrich NJ. Neurocutaneous syndromes and brain tumors. J Child Neurol. 2016;31(12): 1399–1411.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.