Improved prognosis in disseminated histiocytosis.

The prognosis for children with disseminated histiocytosis, previously considered poor, has improved dramatically with the application of modern principles of chemotherapy. Fourteen children with histiocytosis were staged clinically as follows: those without organ dysfunction, stage I; those with organ dysfunction, stage II; and histologically (B, benign and M, malignant). They were treated with either oral chlorambucil or combination chemotherapy with vinblastine and other agents. Clinical staging was of value in predicting response to treatment and prognosis, while histologic staging was of less value. Thirteen of the 14 children responded to treatment and are alive 4 to 67 months (median 12 months) after diagnosis. Two of these relapsed on treatment, and they have responded to a change in therapy. Two children relapsed after stopping treatment and were reinduced with reintroduction of similar therapy. Initial response to treatment suggests a favourable outcome, for children who initially responded to treatment but relapsed subsequently responded to either reintroduction of the same treatment or a change in treatment.