Severe proteus syndrome in an 18-month-old boy.

We describe an 18-month-old Greek boy with macrocephaly, partial gigantism of hands and feet, hemihypertrophy, pigmented nevi, and other anomalies compatible with the Proteus syndrome. Cerebral involvement in a most severe form and at an early age concurs with the suggestion that encephalocraniocutaneous lipomatosis may represent a more circumscriptive manifestation of Proteus syndrome. Localized triggering of several growth factors is a challenging pathogenetic consideration of the syndrome.