OBJECTIVETo study the clinicopathologic features and significance of aberrant CD56 expression in diffuse large B-cell lymphoma (DLBCL).

METHODSThe clinical and pathologic profiles of 10 cases of DLBCL with aberrant expression of CD56 were investigated. Immunohistochemical staining, in-situ hybridization for Epstein-Barr virus encoded RNA and gene rearrangement for IgH and Igκ were carried out.

RESULTSThere were 6 male and 4 female patients. The medium age of patients was 46 years. All of them presented with extranodal lymphoma involvement, with gastrointestinal tract being the commonest site (5/10). Histologic examination showed that most of the atypical lymphoid cells were centroblast-like and demonstrated a diffuse growth pattern. Apoptosis and necrosis were identified in some cases. Immunohistochemical study showed that the tumor cells were positive for CD20 or CD79α and aberrantly expressed CD56. Five cases had the GCB phenotype while the remaining cases had the non-GCB phenotype, according to Hans classification. Bcl-6 was positive in most cases (9/10). All cases showed a high proliferation index by Ki-67. The tumor cells were negative for CD3ε, CD138 and granzyme B. In-situ hybridization for Epstein-Barr virus encoded RNA was performed in 7 cases and none of them showed positive signals. IgH gene rearranged bands were detected in 4 cases (4/6) and Igκ was detected in 3 cases (3/6). Follow-up data were available in 8 patients. Two patients died of disease progression within 5 to 13 months after diagnosis and the other 6 patients were alive 8 to 60 months after therapy.

CONCLUSIONSDLBCL with aberrant expression of CD56 is rare. Most of them present with extranodal involvement, show high frequency of bcl-6 expression and high proliferation index. The patients often have good response to chemotherapy.

Antigens, CD20 ; metabolism ; Apoptosis ; CD56 Antigen ; metabolism ; CD79 Antigens ; metabolism ; Disease Progression ; Female ; Gene Rearrangement ; Granzymes ; metabolism ; Herpesvirus 4, Human ; genetics ; Humans ; Immunophenotyping ; In Situ Hybridization ; Lymphoma, Large B-Cell, Diffuse ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Necrosis ; Phenotype ; Proto-Oncogene Proteins c-bcl-6 ; metabolism ; RNA, Viral ; analysis

OBJECTIVETo investigate the clinicpathologic features and diagnosis of plasmablastic lymphoma (PBL).

METHODSEleven cases of PBL were collected and followed up, with review of the literature. HIV and EBV status and their relationships with the tumor were specially compared as well.

RESULTSIn the current cohort, 10 patients were serologically HIV negative; the male to female ratio was 8 to 3, and the median age was 57 years. Ten cases showed extranodal involvement and one case was nodal based. At presentation, five patients had mid-facial involvement, including sinonasal area (3 cases) and oral cavity (2 cases). Histologically, six were PBL of oral mucosa type, and five were PBL with plasmacytic differentiation. In all cases, the neoplastic cells expressed CD138 and MUM-1, and were negative for CD20 and CD3ε; the median Ki-67 index was 80%. Five cases were EBER1/2 in situ hybridization positive. IgH or/and Igκ gene rearrangement was detected in all five cases examined.

CONCLUSIONSMost patients were no congenital or acquired immunodeficiency in the retrospective study. Of the died patients, EBER1/2 in situ hybridization were negative and their disease staging were Ⅳ, The neoplastic cells were immunoblastic or plasmablastic, sometimes the plasmacytoid cell can be seen and the neoplastic cell had mature plasma cell phenotype, the pathologic diagnosis of the lymphoma is still controversial now. Differentiate with plasma cell neoplasm is difficult, it is necessary to accumulate more cases for advanced study and observation in the future.

Female ; Gene Rearrangement ; Humans ; In Situ Hybridization ; Male ; Middle Aged ; Multiple Myeloma ; Plasma Cells ; Plasmablastic Lymphoma ; diagnosis ; pathology ; RNA, Viral ; metabolism ; Retrospective Studies