Plasmablastic Lymphoma of Small Intestine: A Rare Case Report with Review of Literature.

Plasmablastic lymphoma (PBL) is a rare aggressive neoplasm characterized by diffuse proliferation of large neoplastic cells with plasma cell immunophenotype. Cell of origin of PBL is believed to be a postgerminal center B-lymphocyte or plasmablast. The malignant cells in PBL usually do not express CD20 (B cell marker) but do express markers of plasmacytic differentiation, such as CD38, CD138, or MUM1/IRF4, akin to plasma cell myeloma (PCM). PBL though originally described in the oral cavity, has now been found to occur in extraoral locations as well. Small intestine as a site of PBL has been described very rarely. PBL remains a diagnostic challenge given its overlapping morphologic and immunophenotypic features with other high grade lymphomas and PCM. We report a rare case of PBL of small intestine in a 48 years old HIV infected male patient. To the best of our knowledge this represents sixth case in the literature described in this location. An unusual rare pattern of CD138 positivity by IHC is also reported along with extensive review of literature of PBL in extraoral locations.