Congenital self-healing histiocytosis-X.

Histiocytosis-X (H-X) is heterogeneous clinically, varying from localized benign forms to disseminated fatal forms, but has a relatively uniform and specific pathologic appearance, both by light and electron microscopy. H-X localized to bone or lung has long been recognized. Much less frequent are patients with H-X localized to skin. We report two infants with congenital self-healing H-X, clinically confined to the skin. Prediction of the clinical course from the histology of a H-X lesion is unreliable, especially for cutaneous lesions. We feel that patients with localized forms of H-X should be followed closely for progression of disease but should not be treated aggressively until time is allowed for spontaneous resolution.