Case of plasmablastic lymphoma of the sigmoid colon and literature review.

Plasmablastic lymphoma (PBL) is a rare form of non-Hodgkin's lymphoma that is associated with human immunodeficiency virus (HIV) infection. Although PBL is most commonly observed in the oral cavity of HIV-positive patients, it can also be observed at extra-oral sites in HIV-negative patients. This report represents an unusual case of HIV-negative PBL that occurred in the sigmoid colon. This patient had a history of systemic lupus erythematosus and an underlying immunosuppressive state from long term steroid therapy. The lymphoma cells were positive for CD138, kappa light chain restriction and Epstein-Barr virus and negative for CD20/L26, CD3, CD79a, UCHL1 (CD45RO) and cytokeratin (AE1/AE3). The patient died approximately 2 mo after the operation. In the present paper, we review cases of PBL of the colon in HIV-negative patients.