Historical perspectives of Langerhans cell histiocytosis.

This brief review of the history of Langerhans cell histiocytosis brings us into touch with the history of medicine of the last 100 years and the opportunity to reflect on the progress in medicine in general. Hand, Christian, Schüller, Letterer, and Siwe represent far more than names to attach to eponyms. This historical overview takes us from the first descriptions of the disease in the literature through the modern efforts to take the X out of histiocytosis-X.