[1521] Increase in B/T-Cell Size Ratio Predicts Superior Survival in Peripheral T-Cell Lymphomas with Large B-Cells

Leonard HC Tan, Soo-Yong Tan, Tiffany Tang, Soon-Thye Lim, Daryl CL Tan, Lay-Cheng Lim, Grace LS Kam, Yeh-Ching Linn, Tze-Ping Loh, Miriam Tao, Evelyn SC Koay. Singapore General Hospital, Singapore, Singapore; National Cancer Centre, Singapore, Singapore; National University Hospital, Singapore, Singapore; National University of Singapore, Singapore, Singapore

Background: Pathological prognostication for peripheral T-cell lymphomas (PTCLs) with large B-cell (LBC) proliferations has not been previously investigated by others.
Design: 46 cases were reviewed immunohistologically and by PCR for TCR clonality, and followed up for 1 to 149 months (mean 40 months). Cases whose neoplastic T-cells were on par with or exceeded interspersed LBCs in size were designated “ATEB+ (Atypical T-cell size Equal to or Exceeding large B-cell size)”, with the complement designated “ATEB-“.
Results: 12/46 cases (26%) were ATEB+, comprising 7/25 cases (28%) of angioimmunoblastic T-cell lymphoma (AITL), 4/20 cases (20%) of unspecified PTCL(U) and 1 ALK- anaplastic lymphoma (ALCL). 10/34 (29%) ATEB- cases had Reed-Sternberg-like LBCs (RSL+), of which only 2/25 cases (8%) were AITL but significantly more (8/20 cases or 40%) were PTCL(U) (p=0.012). The median survival of the entire cohort was 22.5 months, without significant separation between AITL and PTCL(U) (p=0.696). However, ATEB+ cases had a median survival of 10 (95% confidence interval [CI] 2 – 26) vs 101 (95% CI 24 – >149) months in ATEB- cases (n=34), 24 of which were RSL- [5-year survival (5ys) 55% (95% CI 32-78%)], with the remaining 10 cases being RSL+ [5ys 80% (95% CI 44-100%)] (p=0.002, Fig A). When restricted to TCR-clonal cases (n=30 comprising 8 ATEB+ and 22 ATEB- cases) the survival separation remained at 10 (95% CI 1 – 23) vs 69 (95% CI 31 – 79%) months respectively; of TCR-clonal ATEB- cases, 16 were RSL- [5ys 44% (95% CI 13-75%)] and 6 were RSL+ [5ys 67% (95% CI 13-100%)] (p=0.007, Fig B).


Conclusions: In PTCLs with LBCs larger (ATEB-, the extreme being RSL+) than the neoplastic T-cells—whatever their absolute size—there is a tendency towards prolonged survival. This may suggest a degree of preservation of T-cell function in terms of trophic cytokine production, associated with more indolent behavior.
Category: Hematopathology

Monday, March 4, 2013 1:00 PM

Poster Session II # 217, Monday Afternoon

 

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