Giant congenital melanocytic naevus associated with Dandy-Walker malformation, lipomatosis and hemihypertrophy of the leg.

A 30-year-old woman presented with congenital hyperpigmented plaques and multiple tumoral lesions. Her left leg was hypertrophic, although the bones were normal. Dermatological examination revealed hyperpigmented macules and plaques with hair on the legs, abdominal and lumbar areas (covering > 60% of the total body surface) and multiple naevi on the face, arms, back and chest. Multiple soft masses of various sizes, some of which colocalized with hyperpigmented plaques, were seen on the trunk and legs. Malignant melanoma was excluded by histopathological examinations of multiple biopsy specimens obtained from the pigmented lesions. Histopathological examination of one of the soft masses showed that it was a lipoma. Cranial magnetic resonance imaging and computed tomography scans showed an enlarged fourth ventricule and vermis hypoplasia (Dandy-Walker malformation; DWM). Neurocutaneous melanosis is a rare combined abnormality of the skin and central nervous system. A few case reports relating to the coexistence of giant congenital melanocytic naevus, lipomatosis and hemihypertrophy have been published in the literature. We report this very rare case of giant melanocytic naevus with lipomatosis, hemihypertrophy of the leg, and DWM.