[Myxoid dermatofibrosarcoma protuberans in childhood].

Dermatofibrosarcoma protuberans is a locally aggressive skin tumor that affects young and middle-aged adults. A number of histological variants have been described, the myxoid type being one of the least common. Microscopically it is formed of a neoplastic growth that is located in the dermis and hypodermis and has a predominant myxoid component. Peripherally there are infiltrating bundles of spindle-shaped cells that are diffusely positive for the CD34 immunohistochemical marker. We report a case of myxoid dermatofibrosarcoma protuberans on a finger of the left hand of a 14-year-old girl. The tumor had been present for at least 10 years. This is the first pediatric case of myxoid dermatofibrosarcoma protuberans at this site. This histological subtype has mainly been described on the extremities in adults and is very rare in children. We discuss the differential diagnosis with other CD34(+) myxoid mesenchymal tumors.