Aleukemic Reticuloendothelioses, Systemic

A group of disorders resulting from the abnormal proliferation of and Tissue infiltration by Langerhans Cells which can be detected by their characteristic Birbeck granules (X bodies), or by monoclonal antibody Staining for their surface CD1 Antigens. Langerhans-Cell granulomatosis can involve a single organ, or can be a systemic disorder.