[1400] Population-Based Heterogeneity in Prevalence, Age Distribution, and Latency Patterns of EBV-Positive Diffuse Large B-Cell Lymphoma

Casey M Inouye, Yi Xie, Lingyun Ji, Susan Groshen, Ajaz Bulbul, Anil Tulpule, Imran N Siddiqi. LAC+USC Medical Center, Los Angeles, CA; University of Southern California, Los Angeles, CA

Background: Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphoma (EBV+ DLBCL) of the elderly is a clinically aggressive subtype of DLBCL occurring in patients >50 years of age. This variant typically shows polymorphous histology, extranodal presentation, and type II/III EBV latency, the latter suggesting age-related immunosenescence. Prevalence varies geographically, being more common in Asian compared to Western populations. The purpose of this study was to evaluate the prevalence, age distribution, and clinicopathologic behavior of EBV+ DLBCL at LAC+USC, a large county hospital in Los Angeles with a predominantly Hispanic patient population.
Design: 98 cases of de novo DLBCL diagnosed from 2003-2012 at LAC+USC were retrospectively identified. Tissue microarrays were constructed (88 total cases) and cases were assessed for histologic features, EBER in-situ hybridization, and IHC staining for CD10, BCL6, MUM1, LMP1, and EBNA2. Clinical features were determined by chart review. Patients with HIV, congenital, or acquired immunodeficiencies were excluded. Overall survival was evaluated using the Cox regression model.
Results: 6 of 88 cases (6.8%) DLBCL cases were EBV+ (defined as greater than 20% EBER+ cells). Median age at diagnosis for EBV+ patients was 38 years (range 20-68), compared to 55 years for EBV- patients (range 26-89). Among the 6 EBV+ patients, only 2 (33%) were >50 years old. There were 5 Hispanic patients and 1 Asian patient (2 born in Mexico, 1 in El Salvador, 1 in Indonesia, and 2 with unknown birthplace). Extranodal involvement was present in 2 cases. 3 showed pleomorphic histology with Reed-Sternberg-like cells and 5 had necrosis. 4 were classified as non-germinal center type by the Hans algorithm. LMP1 and EBNA2 staining were compatible with latency type I pattern in 4 cases and type II/III in the remaining 2 cases. 2 year and 5 year overall survival rates for EBV+ patients was significantly worse than for EBV- patients (both 42 +/- 22% versus 80 +/- 5% and 67 +/- 7%, respectively, p=0.019).
Conclusions: In this predominantly Hispanic patient population with frequent birthplace outside the US, EBV+ DLBCL has a higher prevalence, lower age of onset, and differing EBV latency patterns relative to non-Hispanic Western populations, while the histologic features and aggressive clinical course appear similar. Given this heterogeneity, testing and interpretation of EBV status in DLBCL in immunocompetent patients should be tailored to the demographics of the patient population.
Category: Hematopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 190, Monday Afternoon


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