The aim of the present study is to confirm the histopathological features of aggressive B-cell lymphoma in Papua New Guinea: an Epstein Barr virus (EBV) endemic region. We retrospectively analyzed the immunophenotypic features and expression of EBV-encoded proteins and RNA in B-cell lymphomas in 21 Papua New Guinean children, and compared them to the corresponding features of 17 Japanese children with Burkitt lymphoma (BL). Histological diagnoses of the lymphomas revealed BL in 9 patients; atypical Burkitt/Burkitt-like variant of BL (BLL), 3; diffuse large B-cell lymphoma (DLBCL), 4; B-lymphoblastic lymphoma (B-LBL), 5.
The lymphomas from the Papua New Guinean children indicated a high positive rate for EBV-RNA in situ hybridization (EBV-ISH) (66.7%). With regard to the histological typing, 10 of 12 (83%) patients with BL/BLL, 1 of 4 (25%) with DLBCL, and 3 of 5 (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. Among the patients with EBV-positive BL, 1 patient displayed positivity for EBV-latent membrane proteins (EBV-LMP), albeit BL is usually negative for EBV-LMP. We were unable to detect EBV-positive patients in the 12 Japanese patients who were available for the EBV-ISH evaluation.