Langerhans Cell Histiocytosis

**Semantic type:** Neoplastic Process

**Definition:** 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)

**Synonyms:** - Histiocytosis X - Histiocytosis X - LCH - LCH - Langerhans Cell Granulomatosis - Langerhans cell granulomatosis - Langerhans cell histiocytosis - Langerhans cell histiocytosis - Langerhans cell histiocytosis, NOS