Plasmablastic lymphoma of the colon in HIV negative patient; a case report with literature review.

Introduction: Plasmablastic lymphoma (PBL) is a rare and aggressive variant of diffuse large B cell lymphoma characterized by weak or absent expression of conventional B cell markers and strong expression of plasma cell markers. Very few cases of PBL of the colon have been reported in HIV negative patients. Case presentation: A 57 years female with HIV negative serology, a known case of hypertension under medication presented with right lower abdominal pain associated with vomiting and significant weight loss. On abdominal examination, soft, tender, and globular lump was palpable. Contrast enhanced computed tomography of abdomen and pelvis revealed asymmetrical enhancing mass like wall thickening involving ileocaecal region, caecum, and ascending colon, which on colonoscopy was found to be ulceroproliferative in nature. Open right hemicolectomy was performed and postoperative histopathology and immunohistochemistry results confirmed plasmablastic lymphoma as the final diagnosis. She was treated with nine cycles of chemotherapy. Clinical discussion: Although PBL is commonly found in the oral cavity, and HIV positive patients, it can rarely occur in extra-oral sites, and HIV negative patients. Due to its rarity, no optimal therapeutic approach has yet been defined for the treatment of PBL. It has a poor prognosis, and the overall survival rate has been correlated with international prognostic index score and achievement of complete remission. Conclusion: As plasmablastic lymphoma is rare and highly aggressive, its delayed diagnosis will lead to poor outcome. Thus, awareness about its clinical presentation, histopathological features, and immunophenotype is essential.