A rare form of non-Langerhans-cell histiocytosis (HISTIOCYTOSIS, NON-LANGERHANS-CELL) with onset in middle age. The systemic disease is characterized by infiltration of lipid-laden macrophages, multinucleated giant cells, an inflammatory infiltrate of lymphocytes and histiocytes in the bone marrow, and a generalized sclerosis of the long bones.
