Proliferation of the characteristic histiocyte of histiocytosis X in the skin

Abstract

The proliferation of the characteristic histiocyte of histiocytosis X in the skin of a patient with localized lesions of Hand-Schüller-Christian disease has been studied by counting cells in mitosis and cells that incorporated tritiated thymidine. The mitotic index was very low although about one-quarter of the cells were synthesizing DNA. In the deep dermis, many eosinophils were associated with a decreased tendency of the characteristic cells to synthesize DNA. We conclude that in this patient with a localized type of histiocytosis X, the characteristic cells are stimulated to enter the S phase when they are situated close to the epidermis, but there is no evidence that they divide in the skin subsequently.