Plasmablastic lymphoma may occur as a high-grade transformation from plasmacytoma.
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.
Qing
Xin
X
Department of Pathology, Harbor-UCLA Medical Center, 1000 West Carson Street, Torrance, CA 90509, USA.
Sun
Nora
N
Chang
Elena
E
French
Samuel
S
Ji
Ping
P
Yue
Changjun
C
D000368:Aged; D003937:Diagnosis, Differential; D020031:Epstein-Barr Virus Infections / Q000473:pathology / Q000821:virology; D006678:HIV / Q000235:genetics / Q000276:immunology; D018023:HIV Seronegativity / Q000276:immunology; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D016400:Lymphoma, Large-Cell, Immunoblastic / Q000209:etiology* / Q000473:pathology* / Q000821:virology; D008297:Male; D010954:Plasmacytoma / Q000473:pathology*