Long-term sequelae of histiocytosis X.

Residual disabilities are seen in more than half of children who survive histiocytosis. These problems are secondary to either continuously active disease or scarring of previously affected tissues. Fatal outcome from disabilities are particularly seen with pulmonary disease, either from progressive fibrosis or complicating opportunistic infections. "Second' tumors have been seen in association with radiation: brain tumors, osteosarcoma, and thyroid carcinoma. No cases of chemotherapy-related malignancy have been reported.