Malignant histiocytosis. Immunohistochemical characterization on paraffin embedded tissue.

Clinically, malignant histiocytosis is a malignant neoplasia with poor prognosis. Diseased are lymphnodes (especially cervical nodes), liver, spleen and bones. Few cases become leukemic. The cells show characteristic pale roundish, often indented nuclei, without large nucleoli and with abundant ill-defined cytoplasm. Phagocytosis of erythrocytes and leukocytes, as well as, hemosiderin deposits may serve as indicators for histiocytic, respectively macrophagic qualities. On touch preparation, tumor cells previously had been marked by acid phosphatase and non-spevific esterase, as being histiocytic. - A comparable marking could be carried out on paraffin embedded material with lysozyme (muramidase) and alpha1-antichymotrypsin, by the indirect immuno-peroxidase technique. No correlation could be proven between any special shape of tumor cells or between different grades of cellular atypism and presence or absence of the immunohistochemical reaction. The reaction with lysozyme and alpha1-antichymotrypsin was also tested in other tumors and was found to be positive in a variety of different tumor cells showing degenerative changes, respectively necrobiosis. - But lysozyme and alpha1-antichymotrypsin are markers characteristically found in histiocytes, respectively histiocytic tumor cells. They are apparently less distinct in MH with a larger number of immature histiocytic tumor cells.