Immunohistochemical study on cutaneous histioproliferative lesions.

Immunohistochemical examinations were performed using five kinds of histiocytic markers [S100 protein, lysozyme, non-specific cross reacting antigen with carcinoembryonic antigen (NCA), alpha 1-antichymotrypsin (alpha 1-ACT) and alpha 1-antitrypsin (alpha 1-AT)] in biopsied tissues from histiocytosis X, juvenile xanthogranuloma, xanthoma tuberosum, xanthoma disseminatum, reticulohistiocytic granuloma and multicentric reticulohistiocytoma, all of which have been classified as histiocytic proliferative disorders. Our results suggested that xanthomatous lesions of the skin to be composed of the histiocytic proliferation of two different cell lineages, i.e. S100+lyso-NCA- T-zone histiocytes and S100-lyso+NCA+ tissue macrophages. Only lesions of histiocytosis X were composed of the former cells. It is suggested that these markers will be useful in determining the delineation of the histiocytic system on the basis of functional heterogeneity.