[1514] Majority of the Primary Central Nervous System Large B-Cell Lymphomas Show Activated B-Cell Immunophenotype with a High Proliferation Rate and a Low Incidence of Epstein Barr Virus

Denisa Slova, Laurie Goodell, David Weissmann, Gratian Salaru, Roy Rhodes, Sharathkumar Bhagavathi. UMDNJ - RWJMS, New Brunswick, NJ

Background: Primary central nervous system lymphomas (PCNSL) are uncommon aggressive extranodal non-Hodgkin lymphomas that involve the brain, leptomeninges, eyes, or spinal cord without evidence of systemic disease. Recently, nodal diffuse large B cell lymphoma (DLBCL) has been subclassified into germinal (BCG) and activated B-cell (ABC) types using microarray. GCB subtype DLBCL is associated with better prognosis compared to ABC subtype.
Design: Pathology data files of UMDNJ-RWJMS were searched for diffuse large B cell lymphomas which involved central nervous system (CNS). Detailed history including staging information was obtained to exclude secondary involvement of CNS. Detailed immunohistochemical staining was performed using markers; CD20, CD10, Bcl-6, MUM-1, MIB-1, Bcl-2 and in-situ hybridization for Epstein Barr Virus (EBV, EBER). Lymphomas were subclassified into GCB and ABC subtypes depending on the staining of CD10, BCL6 and MUM1. The expression pattern of CD10+ with or without BCL6 and MUM1 correspond to GCB subtype and expression pattern of CD10- with MUM1+ corresponds to ABC subtype.
Results: A total number of 17 cases of PCNSL were identified in the present study. Immunohistochemical staining showed 2/17 (positive cases/examined cases) for CD10, 15/17 for Bcl-6, 17/17 for MUM-1 and 13/17 for Bcl-2. Majority of the PCNSL showed ABC subtype (15/17, 88%). The proliferation index by MIB-1 ranged from 40 to 90% with a mean of 71%, indicating a high proliferation of lymphoma cells. Only one case was found to be positive for EBV by in-situ hybridization (1/17, 6%).

Immunohistochemistry results
PAX5/CD20CD3/BCL2BCL6CD10MUM1Ki-67EBERSUBTYPE
+ / +- / ++-+40%+ABC
+ / +- / ++-+60%-ABC
+ / +- / ++-+90%-ABC
+ / +- / ++++90%-GCB
+ / +- / ---+90%-ABC
+ / +- / ---+90%-ABC
+ / +- / +++-60%-GCB
+ / +- / ++-+80%-ABC
+ / +- / -+-+90%-ABC
+ / +- / ++-+80%-ABC
+ / +- / ++-+80%-ABC
+ / +- / ++-+80%-ABC
+ / +- / -+-+70%-ABC
+ / +- / ++-+80%-ABC
+ / +- / ++-+70%-ABC
+ / +- / ++-+50%-ABC
+ / +- / ++-+80%-ABC
+ Positive; - Negative; ABC activated B-cell type; GCB germinal center B-cell


Conclusions: Primary CNS DLBCL has an ABC phenotype in the majority of cases with high Bcl-2 positivity and a high proliferation index. The majority of the PCNSL are negative for EBV.
Category: Hematopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 189, Monday Afternoon

 

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