Langerhans cell histiocytosis: a multisystem disorder.

Langerhans cell histiocytosis can involve single or multiple organ/tissue systems and may go undiagnosed for years until it enters the clinician's differential diagnosis framework. We report on a young patient who initially presented with diabetes insipidus and subsequently with pyrexia of unknown origin. She progressed from single system Langerhans cell histiocytosis to multisystem involvement and remains in long-term remission following chemotherapy.