Immunohistochemical staining, APAAP method. (A) DLBCL, centroblastic subtype, CD20 staining with positive tumor cells, × 40; (B) Burkitt-like lymphoma, CD20 staining with negative tumor cells and positive reactive lymphocytes, × 40; (C) DLBCL, centroblastic subtype, CD10 staining with positive tumor cells, × 40; (D) plasmablastic lymphoma, CD10 staining with negative tumor cells, × 40; (E) DLBCL, immunoblastic subtype, CD138 staining with positive tumor cells, × 40; (F) DLBCL, CD138 staining with negative tumor cells and positive reactive plasma cells, × 40; (G) Burkitt lymphoma, MUM1 staining with positive tumor cells, × 40; (H) DLBCL, centroblastic subtype, MUM1 staining with negative tumor cells and positive reactive plasma cells, × 40. Images were visualized in Zeiss Immersol S18N under an Axioskop 2 Plus microscope (Zeiss, Oberkochen, Germany) equipped with a Plan Apochromat 40 ×/1.0 oil objective lens; the iris aperture was 1.0. A Sony 3 CCD color video camera MC3289 (Sony, Tokyo, Japan) and DSH Bilddatenbank software (Greifenstein, Germany) were used for image acquisition.