Plasmablastic lymphoma (PBL) represents a rare type of non-Hodgkin lymphoma associated with human immunodeficiency virus (HIV) infection. The impact of highly active antiretroviral therapy (HAART) in this tumor is poorly known due to its small incidence. This study reports a case of a 33-year-old HIV-positive woman who was referred to the Stomatology Department complaining about a painful gingival growth and cervical nodule both with 20 days of evolution. The lesions appeared 7 months after the patient stopped HAART. The final diagnosis was PBL. After resuming HAART for 45 days, the gingival lesion presented complete remission. The patient continued with HAART alongside chemotherapy. At 24 months follow-up, the patient was stable. The dental surgeon plays an essential role in orientation and retention in care of HIV patients once the adherence of HAART seems to play an important role in PBL development and response to treatment.