Plasmablastic lymphoma of the stomach: an unusual presentation.

Plasmablastic lymphoma (PBL) is listed in the World Health Organization (WHO) classification as a subtype of diffuse large B-cell lymphoma (DLBCL). Some morphologic features of PBL are similar to DLBCL; however, PBL has minimal or no expression of CD20 and leukocyte common antigen. Instead, PBL has been characterized by the plasmablastic morphology of the cancer cells, with high mitotic figures. It is believed to be an aggressive lymphoma. We describe a case of a patient who seemed to pose a diagnostic dilemma, and who was later found to have PBL.