Histiocytic sarcoma (true histiocytic lymphoma): a clinicopathological study of 20 cases

Large-cell non-Hodgkin's lymphomas (T- and B-immunoblastic, centroblastic and true histiocytic lymphomas) have a heterogeneous clinical course. In the present study the clinical and morphological data of 20 cases of histiocytic sarcoma (true histiocytic lymphoma) are presented. Diagnosis was supported by immunohisto-chemistry, cytochemistry, rosette assays and/or electron microscopy. Although the follow-up was relatively short (up to 144 months, mean 26 months), the clinical data differed clearly from the series of large-cell non-Hodgkin lymphomas, recorded in the literature. Differences were found in age distribution with a peak in the third decade, in organ involvement showing a preference for skin, gastrointestinal tract and bone, and in response to therapy. In general, histiocytic sarcoma appears to have a more favourable response to therapy and clinical course than the other large-cell lymphomas (T- and B-immunoblastic and centro-blastic lymphomas). Moreover, preliminary observations in the group of histiocytic sarcomas suggested that the presence of lysozyme and/or 5-nucleotidase and the absence of α1-antitrypsin in the cytoplasm is associated with a better response to therapy and favourable clinical course.