CENTROBLASTIC AND CENTROBLASTIC-CENTROCYTIC LYMPHOMAS ASSOCIATED WITHPROMINENT EPITHELIOID GRANULOMATOUS RESPONSE WITHOUT PLASMA-CELL DIFFERENTIATION - A CLINICOPATHOLOGICAL STUDY OF 12 CASES

To clarify the clinicopathologic features of B-cell lymphoma associate d with prominent epithelioid granulomatous responses other than immuno cytomas, 12 patients were studied. There were six men and six women. T he lymphoma generally affected elderly patients (median age, 58.5 year s) and was mostly nodal in origin, Seven of the 12 patients had a loca lized lesion (stage I or II), and five had an advanced lesion (stage I II or IV), Histologically, four patients showed a follicular growth pa ttern and eight a diffuse growth pattern. Based on the updated Kiel cl assification, nine patients showed centroblastic lymphomas, and three showed centroblastic-centrocytic lymphomas. The epithelioid cells were accumulated in large, poorly demarcated masses. Trabecular fibrosis c ompartmentalized in the lymph nodes, producing a vague nodular pattern in low-power fields. Immunohistochemical studies of the tumor cells r evealed positive membrane staining with L26 in all 12 patients and wit h LN-1 antibody in 9 of 10 patients. Expression of the bcl-2 protein w as present in all seven patients tested. Genotypic investigation exhib ited germline configuration of the immunoglobulin heavy chain gene, th e T-cell receptor beta-chain gene and the bcl-2 gene in all three pati ents investigated. By in situ hybridization, Epstein-Barr virus genome s were detected in only a few tumor cells in three of the patients tes ted. This study indicated that most, if not all, of the B-cell lymphom as with prominent epithelioid granulomatous responses other than immun ocytoma were of follicular center cell origin. Copyright (C) 1996 by W .B. Saunders Company.