Cutaneous Langerhans Cell Histiocytosis Responsive to Topical Nitrogen Mustard.

Langerhans cell histiocytosis (LCH) limited to the skin is rare in adult patients. Given the challenges of prospective clinical trials for this rare disease, there is paucity in data to guide the management of cutaneous LCH. Topical nitrogen mustard is a possible treatment for cutaneous LCH with positive responses in five known adult cases in the literature.