A condition in which cells in the RES grow large and form swellings in bone marrow or destroy bones.
Overgrowth of cells of the reticuloendothelial system, causing either isolated swelling of the bone marrow (eosinophilic granuloma) or destruction of the bones of the skull (Hand-Schuller-Christian disease). The most acute form, starting in infancy and usually rapidly fatal, is associated with tumors containing histiocytes in the internal organs (Letterer-Siwe disease).