Plasmablastic lymphomas and plasmablastic plasma cell myelomas have nearly identical immunophenotypic profiles.
Plasmablastic lymphoma is an aggressive neoplasm that shares many cytomorphologic and immunophenotypic features with plasmablastic plasma cell myeloma. However, plasmablastic lymphoma is listed in the World Health Organization (WHO) classification as a variant of diffuse large B-cell lymphoma. To characterize the relationship between plasmablastic lymphoma and plasmablastic plasma cell myeloma, we performed immunohistochemistry using a large panel of B-cell and plasma cell markers on nine cases of plasmablastic lymphoma and seven cases of plasmablastic plasma cell myeloma with and without HIV/AIDS. The expression profiles of the tumor suppressor genes p53, p16, and p27, and the presence of Epstein-Barr virus (EBV) and human herpes virus type 8 (HHV-8) were also analyzed. All cases of plasmablastic lymphoma and plasmablastic plasma cell myeloma were positive for MUM1/IRF4, CD138, and CD38, and negative for CD20, corresponding to a plasma cell immunophenotype. PAX-5 and BCL-6 were weakly positive in 2/9 and 1/5 plasmablastic lymphomas, and negative in all plasmablastic plasma cell myelomas. Three markers that are often aberrantly expressed in cases of plasma cell myelomas, CD56, CD4 and CD10, were positive in 5/9, 2/5, and 6/9 plasmablastic lymphomas, and in 3/7, 1/5, and 2/7 plasmablastic plasma cell myelomas. A high Ki-67 proliferation index, overexpression of p53, and loss of expression of p16 and p27 were present in both tumors. No evidence of HHV-8 infection was detected in either neoplasm. The only significant difference between plasmablastic lymphoma and plasma cell myeloma was the presence of EBV-encoded RNA, which was positive in all plasmablastic lymphoma cases tested and negative in all plasma cell myelomas. In conclusion, most cases of AIDS-related plasmablastic lymphoma have an immunophenotype and tumor suppressor gene expression profile virtually identical to plasmablastic plasma cell myeloma, and unlike diffuse large B-cell lymphoma. These results do not support the suggestion in the WHO classification that plasmablastic lymphoma is a variant of diffuse large B-cell lymphoma.
Vega
Francisco
F
Department of Pathology, Baylor College of Medicine [corrected] Houston, TX [corrected] USA.
Chang
Chung-Che
CC
Medeiros
Leonard J
LJ
Udden
Mark M
MM
Cho-Vega
Jeong Hee
JH
Lau
Ching-Ching
CC
Finch
Chris J
CJ
Vilchez
Regis A
RA
McGregor
David
D
Jorgensen
Jeffrey L
JL
D000328:Adult; D000368:Aged; D015703:Antigens, CD / Q000032:analysis; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000032:analysis; D020031:Epstein-Barr Virus Infections / Q000276:immunology / Q000473:pathology / Q000821:virology; D005260:Female; D004854:Herpesvirus 4, Human / Q000235:genetics; D019288:Herpesvirus 8, Human / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D017403:In Situ Hybridization; D019394:Ki-67 Antigen / Q000032:analysis; D008223:Lymphoma / Q000276:immunology / Q000473:pathology* / Q000821:virology; D016483:Lymphoma, AIDS-Related / Q000276:immunology / Q000473:pathology / Q000821:virology; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000276:immunology / Q000473:pathology* / Q000821:virology; D010950:Plasma Cells / Q000276:immunology / Q000473:pathology* / Q000821:virology; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins / Q000032:analysis; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D051560:Proto-Oncogene Proteins c-bcl-6; D014157:Transcription Factors / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis
D015703:Antigens, CD; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051560:Proto-Oncogene Proteins c-bcl-6; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53