Histological characteristics of 21 Papua New Guinean children with high-grade B-cell lymphoma, which is frequently associated with EBV infection.

The aim of the present study was to confirm the histopathological features of aggressive B-cell lymphoma in Papua New Guinea (PNG)-an EBV endemic region. The immunophenotypic features and expression of EBV-encoded proteins and RNA in B-cell lymphomas were analyzed in 21 PNG children, and compared to the corresponding features of 17 Japanese children with Burkitt lymphoma (BL). Histological diagnosis of the lymphomas from the PNG children was BL in nine patients; atypical Burkitt/Burkitt-like variant of BL (BLL) in three; diffuse large B-cell lymphoma (DLBCL) in four; and B-lymphoblastic lymphoma (B-LBL) in five. The lymphomas from the PNG children had a high positive rate on EBV-RNA in situ hybridization (EBV-ISH; 66.7%). With regard to the histological typing, 10 of 12 patients (83%) with BL/BLL, one of four (25%) with DLBCL, and three of five (60%) with B-LBL were positive for EBV-ISH. The findings of EBV-positive B-LBL were surprising because it is commonly considered that lymphoblastic lymphoma is not associated with EBV. EBV positivity was not detected in the 12 Japanese patients who were available for the EBV-ISH evaluation. It is concluded that it is possible that a proportion of DLBCL and B-LBL besides BL/BLL are associated with EBV in endemic region.