[1364] Plasmablastic Lymphomas – Immunophenotypic Spectrum and MYC Translocation.

Tanuja Shet, Sridhar Epari, Suhas Dhende, Manju Sengar, Reena Nair. Tata Memorial Hospital, Mumbai, Maharashtra, India

Background: Pathologists often face a problem of differentiating Plasmablastic lymphoma(PL) from diffuse large B cell lymphoma(DLBL) and plasma cell tumors even in HIV positive patients. This study was an attempt to categorise PL immunophenotypically using a panel of antibodies and also evalaute the incidence of MYC translocation recently reported in literature.
Design: The 102 PL studied were selected from a total of 249 AIDS related lymphomas accessioned at our institute. Immunohistochemistry was performed using the ABC technique and a wide panel of antibodies. We also evaluated a small number for the MYC translocation using the Vysis LSI IGH/MYC, CEP 8 tri-color, dual fusion translocation probe. Presence of Epstein Barr virus was assesed by using Novocastra EBER-ISH kit.
Results: Oral cavity was commonest site of presentation followed by cervical nodes, anorectum and soft tissue. All anorectal tumors occurred in homosexual men, while other patients had heterosexual behaviour. CD4 counts only in 17% were above 200. All tumors has plasmacytoid cells with 45 tumors showing myeloma like; 48 blastic and 9 with anaplastic morphology. The immunophenotypic expression is given in the Table.

Immunophenotypic pattern of Plasmablastic lymphoma
Marker% expression

Myeloma like PL were XBP 1 positive. CD20 was expressed in 3 tumors only. Two EBER-ISH positive cases expressed EBNA2 and EBVLMP1 while others were negative. CD10 expression was strong in one case and weak in 9 cases. HHV8 (LNA1), ALK1, cyclin D1 and CD40 were absent in most tumors. MIB1 was >80% in 78% of tumors. Two tumors expressed CD4 and CD3 besides MUM1, but lacked T cell receptor rearrangements. Both these occured in severely immunodefecient patients. Three of the 14 PL evaluated had MYC translocation one with multiple fusion signals. Two of these were EBER negative. Therapy and follow up was available in 45 patients. While the none of the immunophenotypic features affected survival, type of treatment and CD4 counts influenced survival.
Conclusions: As seen from our study the PL has a vide immunophenotypic pattern and MYC rearrangements overlapping with DLBL and myeloma but a wide panel will help in evaluation. However none of the immunophenotypic features affected the prognosis in the limited number evaluated.
Category: Hematopathology

Wednesday, March 2, 2011 1:00 PM

Poster Session VI # 220, Wednesday Afternoon


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