Clinicopathological features of Epstein-Barr virus-positive diffuse large B-cell lymphoma in elderly

Abstract

To investigate the clinicopathological features of EB virus positive diffuse large B-cell lymphomas (EBV + DLBCL) of the elderly. Four hundred and ninety-six cases of DLBCLs were retrospectively studied by in situ hybridization (ISH) to detect the EBV in tumor cells, and by immunohistochemistry to evaluate the expression of CD10, CD20, CD30, CD79a, bcl-6, bcl-2, MUM-1, CD5, CD3, TIA-1 and Ki-67 protein. Their clinicopathological correlations were analyzed. Of the 59 cases of EBV + DLBCL, 48 cases were EBV positive. The median age of these EBV + DLBCLs was 73 years with male predominance (1.4:1). There were 11 cases with nodal presentation only, 18 cases with extra-nodal presentation and 19 cases with both lymph nodal and extra-nodal involvements, whereas about one third cases with more than one extra-nodal involvement. Thirty-five patients presented with advanced disease (Ann Arbor stage III/IV). A performance status was available in 36 cases and 5 cases had performance status of more than 1. Seven of 30 patients were found with high lactate dehydrogenase value (more than twice of the normal). An IPI-score was calculated in 30 cases and 18 cases had an intermediate/high IPI-score (3-5). The median survival for these patients was 35 months. Morphologically, EBV + DLBCLs of the elderly generally showed a diffuse and polymorphic proliferation of large lymphoid cells with varying degrees of reactive components including small lymphocytes, plasma cells, histiocytes, and epithelioid cells. These tumor cells were frequently characterized by a broad range of B-cell maturation, containing centroblasts, immunoblasts, and Hodgkin- and Reed-Sternberg (HRS)-like giant cells. The study cohort was further morphologically divided into large cell lymphoma subtypes (n = 33) and polymorphic lymphoma subtypes (n = 14) and one case with mixed subtype. Immunohistochemical studies showed that tumor cells were positive for CD20 (47/48) and/or CD79a (45/45) in almost cases. Tumor cells were MUM-1-positive in the majority of the cases (44/47) and were stained for CD10 or bcl-6 in a few cases. Expression of bcl-2 and CD30 was observed in 80.0% (28/35) and 28.9% (11/38) cases, respectively, and most of the cases (33/39) had a high proliferative index (by Ki-67 with a 50% cut-off point). Compared with other EBV + DLBCLs, except the older age and low frequency of bcl-6 staining, no other significant differences were observed in EBV + DLBCLs of the elderly. EBV + DLBCLs of the elderly constitute a distinct clinicopathologic subtype of DLBCL, although many clinical and histological features with EBV + lymphomas are similar with that of younger ages. Differential diagnosis from other types of lymphomas should also be considered.