The osseous manifestations of sinus histiocytosis with massive lymphadenopathy.

The cases of five patients who had sinus histiocytosis with massive lymphadenopathy accompanied by osseous involvement by the disease are presented. Four of the five patients were children. The bone lesions were multiple in four cases and solitary in one. The long bones were most commonly involved (three patients); other bones affected were the skull, vertebral bodies, pelvis, phalanges, metacarpals, and ribs. Roentgenograms showed lytic lesions with ill-defined, non-sclerotic margins. Microscopically, the lesions consisted of an inflammatory infiltrate composed primarily of mature histiocytes (sometimes demonstrating lymphocytophagocytosis) and accompanied by plasma cells and lymphocytes. The roentgenographic differential diagnosis includes histiocytosis X, metastatic malignancy, sarcoidosis, storage disorders, and the bone lesions of neurofibromatosis.