Pure cutaneous histiocytosis X.

A 38-month-old boy presented with nodules in the skin of the genital region present for 2 1/2 years. These later spread to the skin of the trunk, head, and extremities. A complete clinical workup could not reveal involvement in any other organ sites and biopsy of one of the cutaneous lesions was diagnosed as histiocytosis X. Because the child was in generally good condition, no treatment was given. Follow-up revealed that the disease had remained limited to the skin, where 15% of the lesions disappeared spontaneously.