Langerhans cell histiocytosis in the adult.

A study of 47 well-documented patients with Langerhans cell histiocytosis (LCH) showed a slight female preponderance, with onset as late as the ninth decade. The skin was the commonest site of presentation, but pulmonary and bone involvement was frequent. Patients with single-site disease did best. The worst prognosis was seen in the elderly or those with organ dysfunction. A high incidence of associated malignant disease was seen, which could precede, be coincidental with, or occur after a diagnosis of LCH.