Tags: Disease.
Letterer–Siwe disease is an old name for Langerhans cell histiocytosis (LCH) from a time where LCH was thought to be several different diseases; Letterer–Siwe disease Hand-Schuller-Christian disease Eosinophilic granuloma and Hashimoto-Pritzker disease. Later they were all put together under the name Histiocytosis X. The X was found to be the Langerhans cell a dendritic white blood cell.