Morphologic and immunohistochemical features of O-DLBCLs. (A) Infiltration of pleomorphic B cells with entrapment of preexisting bone (black arrowhead) in an example of PB-DLBCL. (B) Pleomorphic B cells in a case of PB-DLBCL with large and irregular nuclei with a cleaved, multilobulated appearance and small nucleoli. (C) Pleomorphic B cells in a case of disseminated-DLBCL with large nuclei and prominent large nucleoli with an immunoblastic/plasmablastic appearance. (D) Diffuse staining of CD20 in PB-DLBCL. (E) Diffuse staining of CD10 in an example of PB-DLBCL with a GCB phenotype, according to the Hans algorithm. (F) Strong diffuse staining of MUM1 in an example of disseminated-DLBCL with an ABC phenotype.