label: Langerhans Cell Histiocytosis
label_lc: langerhans cell histiocytosis
description: A neoplastic proliferation of Langerhans cells which contain Birbeck granules by ultrastructural examination. Three major overlapping syndromes are recognized: eosinophilic granuloma, Letterer-Siwe disease, and Hand-Schuller-Christian disease. The clinical course is generally related to the number of organs affected at presentation. (WHO, 2001)