HIV-negative plasmablastic lymphoma attaining sustained remission with bortezomib-combined dose-adjusted EPOCH therapy.

A 61-year-old, HIV-negative, immunocompetent woman was admitted to our hospital for significant weight loss, painful swelling of her right cheek, and rapid growth of a tumor in the right hard palate. A CT scan revealed a neoplastic lesion in the right maxillary sinus, extending to the surrounding soft bone tissue and oral cavity, as well as multiple osteolytic lesions in the skull. A pathologic examination revealed that the neoplastic cells in the oral cavity were plasmablasts tending to appear as differentiated plasma cells. The tumor cells strongly expressed CD138, Vs38c, EBER, and MYC, and were negative for CD20 and CD19. The MIB-1 index was 90%, and MYC/IgH fusion gene was detected by fluorescence in situ hybridization analysis. Based on these clinical and pathological findings, we confirmed the diagnosis of plasmablastic lymphoma. This disease has characteristics of aggressive lymphoma originating from differentiated plasma cells. Treatment was initiated with dose-adjusted EPOCH added to a concurrent bortezomib regimen. After completion of four cycles, the patient achieved and sustained complete remission.