Histiocytosis X. III. Clinical value of serial biopsies.

In a retrospective review of sequential biopsies in 8 cases of histiocytosis X, 2 developed xanthomatous or fibrous lesions, 3 remained unchanged, whereas 3 developed malignant disease, one Hodgkin's disease and 2 malignant histiocytosis. A possible progression from benign, well differentiated to malignant histiocytic lesion is discussed, and the importance of achieving a microscopic diagnosis is emphasized.