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Neuroradiology

Phakomatosis

(Greek for "birthmark" or "spot), congenital neurocutaneous syndrome manifesting with central nervous system and cutaneous disorders. In these conditions the lesions mainly affect structures of ectodermal origin, that is, the nervous system, the skin, the retina and the globe and, to a lesser extent, the visceral organs.

The four major phakomatoses described in the literature are reported in Table I.

Phakomatosis, Table 1.

Descriptive nameEponym
Neurofibromatosis type I (NF1)von Recklinghausen's disease
Neurofibromatosis type 2 (NF2)Bilateral VIIIth nerve schwannoma
Tuberous sclerosisBourneville's disease
Encephalotrigeminal angiomatosisSturge Weber disease
Retinocerebellar angiomatosisvon Hippel Lindau disease

Although they are defined as "neurocutaneous" conditions, even in some of the major phakomatoses, for example, von Hippel Lindau disease, the cutaneous manifestations are lack.

Other recognized neurocutaneous syndromes include: ataxia-telangiectasia or Louis-Bar's syndrome, Wyburn Masons syndrome, Osler Rendu Weber disease, Klippel Trnaunay Weber syndrome, meningoangiomatosis, neurocutaneous melanosis, epidermal naevus syndrome, basal-cell naevus syndrome, miscellaneous melanocytic phakomatoses and Cowden disease.

The differential diagnosis is based on clinical examination, imaging studies (both CT and MR) of the brain, spine and body, and on gene mapping, which allows genetic counselling.

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