Histiocyte proliferating diseases in dermatologic fields.

Histiocyte proliferating diseases that we often experience in the dermatologic clinics include histiocytosis-X particularly Letterer-Siwe disease, non-X histiocytosis such as xanthogranuloma, multicentric reticulohistiocytosis, xanthoma disseminatum, and verruciform xanthoma, and fibro-histiocytic tumors represented by dermatofibroma, dermatofibrosarcoma protuberans, and malignant fibrous histiocytoma, as well as malignant histiocytosis. The other diseases, for example, congenital self-healing reticulohistiocytosis and generalized eruptive histiocytoma may be observed in very rare instance. We investigated cell types by using immunohistochemical markers for the prolifearting histiocytic cells on the paraffin sections from 40 cases. A clear result was obtained that S-100 positive cells belonging to T-zone histiocyte lineage are proliferating in histiocytosis-X, while lysozyme positive mononuclear phagocytes are the major cell type in malignant histiocytosis. Although in the rests of the diseases cells are positively reacted for α1-antichymotrypsin, α1-antitrypsin and vimentin, differentiation of the diseases by such immunomarkers was not enabled. There was a tendency that non-X histiocytosis represented by xanthogranuloma showed stronger reactivity for α1-antichymotrypsin and α1-antitrypsin, whereas the cells in fibro-histiocytic tumors are rather strongly positive for vimentin. Further studies are required for the proliferating cells positive for α1-antichymotrypsin, α1-antitrypsin and vimentin.