[1380] Immunohistochemical and Genetic Evaluation of Cyclin D1 Positive Diffuse Large B-Cell Lymphomas in a Large Series

Kate E Grimm, Renuka Agrawal, Lawrence Weiss, Dennis P O'Malley. Clarient Inc./GE Healthcare, Aliso Viejo, CA

Background: Diffuse large B cell lymphomas (DLBCLs) are the commonest type of non-Hodgkin lymphomas; however cyclin D1 expression is rarely reported. We evaluated a series of 347 DLBCLs in a western population spanning the years from 2009-2012 and identified 10 cases of DLBCL with cyclin D1 expression (3%). These were further evaluated comparing their immunohistochemical and genetic profiles.
Design: 347 cases were evaluated using an extensive panel of immunohistochemical stains (CD20, CD3, CD5, CD10, cyclin D1, BCL6, BCL2, EBER, Ki67, and CD30) and a panel of FISH studies (including MYC, IGH/BCL2 and BCL6). In this series we identified 10 cases of DLBCL with cyclin D1 expression by immunohistochemistry.
Results: Six cases were nodal (60%) and four cases were extranodal (40%). Sites of involvement included: testicle (1), cervical (4), inguinal (1), axillary (3) and soft tissue (1). Nine cases did not express CD5 (90%), one case co-expressed CD5 and CD10 with no history of chronic lymphocytic leukemia. Three of five cases expressed CD30 (60%). BCL2 expression by immunohistochemistry was seen in all cases (100%). One case expressed EBV (10%). Four of seven cases harbored a BCL6 translocation (57%); one case showed both BCL6 translocation and IGH/BCL2 translocation. One case of seven showed a MYC translocation (14%). Four of seven cases stained as non-germinal center (GC) origin using the Hans classifier (57%) three of seven cases stained as GC origin (43%). The three cases classified as GC by the Hans classifier stained as non-GC origin by tally method.
Conclusions: In our experience cyclin D1 expression is exceedingly rare in DLBCLs (3%). They have a high frequency of BCL6 translocations (57%) and usually express BCL2 by immunohistochemistry. They show variation in clinicopathologic features, immunophenotype and genetics. Many are nodal and are mainly classified as the non-germinal center B-cell type, suggesting a possible clinical aggressiveness. These features are in contrast to cyclin D1 negative nodal and extranodal DLBCL.
Category: Hematopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 194, Monday Afternoon

 

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