Differential diagnosis of BL, B-UNC/BL/DLBCL, and DLBCL of the GCB type. B-UNC/BL/DLBCL is generally associated with a complex karyotype containing both MYC and BCL2 translocations. BCL2 translocations are found in approximately 30% of the GCB type of DLBCL, but MYC translocation should be absent, and if a dual translocation is found, the case should be classified as B-UNC/BL/DLBCL. Morphologically, BL is composed of medium-sized cells, with minimal nuclear variation. Cell size is largest in DLBCL, and B-UNC/BL/DLBCL is generally composed of cells of intermediate to large size, with greater variability than BL.