Clinicopathologic, enzyme and histochemical studies of centrocytic (mantle cell) lymphoma: comparison with other types of low-grade B cell lymphoma based on the updated Kiel classification.

Lymph nodes from 21 cases of malignant lymphoma of a centrocytic (mantle cell) type, (ML, cc (mc)) were examined. All the cases had monoclonal surface immunoglobulin (sig) M and/or D, but were negative for CD10 (CALLA), and CD11c (LeuM5). Lymphoma cells with CD25 (anti-Tac)+, CD5 (Leu1)+, and alkaline phosphatase (ALPase)- in eight cases showed bone marrow involvement (10-66% of the nucleated cells; mean 32 +/- 18%) but with no leukemic changes. These eight cases had a similar phenotype and were distributed by the lymphoma cells to the examined B-chronic lymphocytic leukemia. Seven cases showed an infiltration of CD25-, CD5+, and ALPase- lymphoma cells, in which only two cases showed focal bone marrow involvement. There was a close relationship between CD25 expression and bone marrow invasion by the lymphoma cells in ML, cc (mc). Three of the six CD25- and CD5- cases presented zonal proliferation of ALPase+ lymphoma cells with round nuclei and a high anti-proliferating cell nuclear antigen/cyclin (PCNA/c) rate in the mantle zone and paracortex, accompanied by a prominent interdigitating dendritic and histiocytic cell reaction. Examined CD25-, CD5- and ALPase+ lymphoma showed a neoplastic counterpart of so-called marginal zone lymphocytes, which was different from other cases of ML, cc (mc). Lymphoma cells in ML, cc (mc), except for those of the so-called marginal zone lymphoma, might be derived from slgM+, D+/-, CD25+/-, CD5+/-, ALPase-, CD10- and CD11c- lymphocytes present in the mantle zone and primary lymph follicles.(ABSTRACT TRUNCATED AT 250 WORDS)