[Solitary mastocytoma].

A case is reported of a four--month--old male infant with mastocytoma localized on antero--internal side of left leg. It was a single lesion seen since birth, of tumoral aspect, about 3.5 x 2 x 0.8 cms., light brown color. The pathologic study confirmed the diagnosis. The course was uneventful and disappeared spontaneouly in one year.