Centrocytic lymphoma: a distinct clinicopathologic and immunologic entity. A multiparameter study of 18 cases at diagnosis and relapse.

The clinical, pathologic, and immunologic aspects of malignant lymphoma of centrocytic type (ML,cc) were studied at diagnosis and often at relapse in 18 patients. The typical patient was a middle-aged or older man with adenopathy, often massive splenomegaly, hepatomegaly, marrow involvement, and, not infrequently, peripheral blood involvement. Histopathologically, ML,cc had a diffuse or vaguely nodular growth pattern with, predominantly, cells resembling centrocytes (cleaved follicular center cells) sometimes with admixed small round lymphocytes but with virtually no transformed cells. In 2 cases the neoplastic cells formed a mantle zone around reactive-appearing follicles. Cell suspensions and frozen sections revealed the monoclonal B-cell nature of all but 1 nonmarking case, and the polyclonality of the follicles in the 1 mantle zone case tested. The B cells had some, but not all, characteristics of both normal mantle and follicular center cells when eight nodes were studied with the use of a panel of monoclonal antibodies, peanut lectin, and endogenous alkaline phosphatase activity. Of 13 patients who underwent repeat biopsies, 1 developed a high grade unclassifiable B-cell lymphoma, and 6 had less marked changes. None of 7 patients tested had a change in light chain class. In conclusion, ML,cc is a distinct entity separable from other B-cell lymphomas in which either centrocytes or small round lymphocytes predominate.