Unexpected plasmablastic lymphoma in a young adult with unknown HIV infection: case report.

Background: Plasmablastic lymphoma (PBL) is a rare, highly aggressive lymphoma of plasma cell differentiation. It commonly presents as an Epstein-Barr virus (EBV)+ oral lesion in an immunodeficient patient, predominately human immunodeficiency virus (HIV)+ patients. These aggressive lesions often demonstrate an immunoblastic or plasmablastic morphology with a typical immunohistochemical profile. The current case is unique due to the location at presentation, immunohistochemical features, and unknown presence of HIV infection in a young adult male. Case Presentation: We present an unexpected case of PBL found in a rare extra-oral location in a young adult male with undiagnosed HIV infection presenting as a perianal hemorrhoid mass/abscess. Swift treatment for HIV and the PBL resulted in complete remission and markedly improved CD4 counts. Conclusions: This case highlights the importance of testing for HIV along with acquiring a thorough social/clinical history when a PBL is encountered. Although the overall prognosis of PBL is dismal with a median survival of about 6-11 months, a timely accurate diagnosis and prompt chemotherapy with an appropriate regimen along with antiretroviral therapy (ART) may still achieve a successful outcome with a relatively reasonable long-term remission like in our reported case.