The patient was a 73-year-old male who came to our hospital with a chief complaint of pain and swelling of the left side of his jaw. Computed tomography revealed a mass in his left gingiva but no bone destruction. No lesions were observed at any other sites, and an incisional biopsy was performed on the gingival mass on the left side. Histologically, the mass was a diffuse large B-cell lymphoma (DLBCL), and it was CD20-positive, and CD5-negative, CD10-negative, surface immunoglobulin-negative, and Epstein-Barr virus-encoded RNA (EBER)-negative. A serum Human immunodeficiency virus (HIV)-antibody test was negative. A complete remission was achieved after 6 courses of systemic combination chemotherapy, and the complete remission has been maintained for approximately 3 years. According to the literature, primary gingival DLBCL have a high Ki-67-positive rate and many of the cases are stage I and international prognostic index low-risk. However, HIV patients have a high EBER-positive rate and a high risk of developing a CD20-negative, CD138-positive plasmablastic lymphoma, and they have a poor prognosis. By contrast, limited-stage primary gingival lymphomas whose data can be used have been rare in human immunodeficiency virus-negative patients, and only 12 cases, including our own, have ever been reported. Many of the patients have been around 65 years of age, and all of the cases have been CD20-positive, CD138-negative DLBCLs, and the CD5-negative, Epstein-Barr virus-positive rate has been low, with most cases having been non-germinal-center B-cell-like. The prognosis for relapse-free survival has been favorable.
Keywords: CD20; Diffuse large B-cell lymphoma; gingiva; human immunodeficiency virus; plasmablastic lymphoma.