Plasmablastic lymphoma may occur as a high-grade transformation from plasmacytoma

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• 作者：Xin Qing^a ; Nora Sun^a ; Elena Chang^a ; Samuel French^a ; Ping Ji^a ; Changjun Yue ; ^a ; ^{yuec@LabCorp.com}
• 关键词：Plasmablastic lymphoma ; Epstein– ; Barr virus ; Plasmacytoma ; Multiple myeloma ; Pathogenesis ; Electron microscopy
• 刊名：Experimental and Molecular Pathology
• 出版年：2011
• 出版时间：February 2011
• 年：2011
• 卷：90
• 期：1
• 页码：85-90
• 全文大小：2855 K

文摘

Plasmablastic lymphoma (PBL) is an uncommon aggressive lymphoma arising most frequently in the oral cavity of HIV-infected patients. Rare cases of PBL have been reported in extraoral sites, particularly extranodal sites, as well as in immunocompetent patients. We report an unusual case of PBL in a 69-year-old, HIV-negative non-immunocompromised man presenting with generalized lymphadenopathy. To our knowledge, this is the first case of PBL presented as primarily generalized lymphadenopathy in HIV-negative patients. Histologic examinations of cervical, inguinal and axillary lymph nodes demonstrated a neoplastic proliferation of large cells with extensive necrosis. The neoplastic cells formed sheets with a relatively cohesive growth pattern interspersed by small lymphocytes and plasma cells. The large tumor cells expressed MUM1, OCT-2 and BOB.1, and were negative for CD138, CD38, AE1/AE3, melan A, PLAP, S100, vimentin, CD117, CD30, ALK-1, leukocyte common antigen (CD45), T-cell, B-cell and histolytic markers, CD56, CD10 and BCL-6. The proliferation index by Ki-67 immunohistochemistry was approaching 100 % . In situ hybridization for Epstein–Barr Virus-encoded RNA (EBER) was positive in large malignant cells. A diagnosis of PBL was made. These findings indicate that PBL should be included in the differential diagnosis of an HIV-negative, immunocompetent patient with generalized lymphadenopathy. The adjacent plasma cells were positive for CD138 and CD38 and show kappa-light chain restriction, but without EBER expression, raising the possibility of a preexisting or concurrent plasmacytoma and that the PBL may be a high-grade transformation from a preexisting plasma cell neoplasm following Epstein–Barr virus infection. Electron microscopy showed numerous circumferential long slender peripheral cytoplasmic projections in the large tumor cells, suggesting that some of the previously reported large B-cell lymphoma with cytoplasmic projections may actually be PBL.