Solitary plasmacytoma associated with Epstein-Barr virus: a clinicopathologic, cytogenetic study and literature review.

Solitary plasmacytoma (SP) is an uncommon, indolent tumor of plasma cell neoplasms that presents as a mass lesion in extramedullary sites. Evidence of Epstein-Barr virus (EBV) infection is frequently associated with various lymphatic and hematopoietic malignancies but is relatively rare in SP. Moreover, it is essential to distinguish EBV-positive plasmacytoma from plasmablastic lymphoma. In this study, we found 4 EBV-encoded RNA (EBER)-positive patients among 46 consecutive immunocompetent patients of SP and compared the clinicopathologic features of these patients with those of the EBER-negative cohort. In the 4 EBER-positive patients, the common presenting feature was a local mass lesion without symptoms of chronic active EBV infection. Upon histologic examination, neoplastic cells demonstrated well-differentiated morphology in the absence of plasmablastic lymphoma components. Fluorescence in situ hybridization analysis showed that all cases were negative for del13q14, t(11;14)(q13;32) and MYC rearrangement but that 1 case had cytogenetic aberrations involving del17p13. Follow-up data revealed that EBER-positive patients had benign prognoses without aggressive clinical course and that there was no significant difference in the overall survival time between the 2 groups, but EBER-positive patients were more likely to have disease progression (relapse/progression to multiple myeloma) compared with EBER-negative patients. More case studies are needed to better understand the impact of EBV on disease pathogenesis and development in immunocompetent patients of SP.