The Department of Medical Research of the 251 Hellenic Air Force & VA General Hospital has been assessed and evaluated by the National Committee for rare diseases as a candidate expert center for Langerhans’ Cell Histiocytosis (LCH) and Erdheim Chester Disease (ECD ) and was officially recognized as such at a National level in November 2019 (official Gov. gazette No 4269, issued Nov 22, 2019 by a common ministerial degree).