Plasmablastic lymphoma (PBL) is a rare and aggressive form of mature B cell neoplasms almost exclusively identified in patients infected with the human immunodeficiency virus (HIV). The small number of HIV-negative PBL cases reported in the literature to date is composed of single case reports and small case series which characteristically are present involving the oral cavity mucosa or gingiva. We present a 72-year-old HIV-negative Australian patient without any cause of immunodeficiency, with an isolated left maxillary sinus PBL.