Congenital or hereditary conditions with lesions of both the skin and the nervous system, both of which are derived from ectoderm, have been traditionally considered together as neurocutaneous disorders. The earlier term phakomatosis (derived from the Greek word phakos, meaning ‘lentil,’ ‘lens,’ or ‘mother spot’) was devised by van der Hoeve to describe tuberous sclerosis and von Recklinghausen neurofibromatosis, disorders with characteristic cutaneous lesions and the potential for tumor formation. Although the term phakomatosis was widely used for several years, the gradual inclusion of conditions with vascular and other skin lesions and disorders without an increased tumor risk made the broader concept of neurocutaneous syndromes more appropriate.

The broader delineation of neurocutaneous syndromes exploits several types of skin and hairabnormalities in addition to the hyperpigmented and hypopigmented maculae that originally defined the phakomatoses (Tables 1.1 and 1.2). Many of these disorders also have important ophthalmologic signs (Table 1.3), and while tumor formation is no longer a required feature of neurocutaneous syndromes, several of them do carry a substantial risk of benign or malignant neoplasms (Table 1.4). Syndrome diagnosis also facilitates the recognition of cardiac (Table 1.5), gastrointestinal (Table 1.6), or other complications.

Neurocutaneous syndromes, by definition, promote neurological dysfunction, but not all of them directly affect the central nervous system.