Unique presentation of a plasmablastic lymphoma superficially involving the entire large bowel.  Plasmablastic lymphoma (PBL) is an uncommon, aggressive B-cell lymphoma mostly occurring in the oral cavity of human immunodeficiency virus (HIV) positive patients, but also described in extraoral sites and in HIV negative patients. One of the relatively common extraoral sites of PBL is the gastrointestinal (GI) tract. Few cases of PBL have been reported in association with inflammatory bowel disease (IBD). Here, we describe the unique presentation of a PBL involving the large bowel superficially along its entire length and without forming a tumor mass in an HIV negative patient with a recent diagnosis of ulcerative colitis.