SMALL B-CELL NON-HODGKINS-LYMPHOMAS WITH SPLENOMEGALY AT PRESENTATIONARE EITHER MANTLE CELL LYMPHOMA OR MARGINAL ZONE CELL LYMPHOMA - A STUDY BASED ON HISTOLOGY, CYTOLOGY, IMMUNOHISTOCHEMISTRY, AND CYTOGENETIC ANALYSIS

Only 1 to 2% of all non-Hodgkin's lymphomas (NHL) present with an enla rged spleen, most of them ''small B-cell lymphomas.'' Recently, severa l reports have identified these lymphomas as marginal zone B-cell lymp homas, We reviewed 39 cases of NHL presenting with an enlarged spleen without lymphadenopathy, documented by fixed and frozen material. Two were peripheral T-cell lymphomas, four diffuse large B-cell lymphomas, and 14 hairy cell leukemias. The remaining 19 belonged to the ''small B-cell'' category and constitute the focus of our study. Subtyping wa s achieved by combining morphology, immunophenotype, and cytogenetic f eatures according to the proposal of the International Lymphoma Study Group; in addition, analysis of the peripheral blood and bone marrow s mears was performed adopting the French-American-British (FAB) criteri a. From this study, we can conclude that most ''small B-cell'' NHL of the spleen were either mantle cell lymphomas or marginal zone cell lym phomas and, by peripheral blood analysis, that the mantle cell lymphom as corresponded to intermediate lymphocytic lymphoma and the marginal zone cell lymphomas to splenic lymphomas with villous lymphocytes. As a result, several diagnostic criteria can be proposed that may be help ful in differentiating mantle cell lymphoma from marginal zone cell ly mphoma in the spleen.