[1343] Extranodal NK/T-Cell Lymphomas, Nasal Type of γδ T-Cell Origin Are Not Rare.

Tawatchai Pongpruttipan, Sanya Sukpanichnant, Thamathorn Assanasen, Pongsak Wannakrairot, Wasana Kanoksil, Paisarn Boonsakan, Kanita Kayasut, Winyou Mitarnun, Adriana Garcia, Elias Campo, John Choi, Steven H Swerdlow. Siriraj Hosp, Bangkok, Thailand; Chulalongkorn Hosp, Bangkok, Thailand; Ramathibodi Hosp, Bangkok, Thailand; Prince of Songkla U, Hat-Yai, Thailand; U Barcelona, Spain; U Penn Sch of Med, Philadelphia; U Pitt Sch of Med, Pittsburgh

Background: Most extranodal NK/T-cell lymphomas, nasal type (ENKTL) are of NK-cell origin with a minority of “cytotoxic T-cell origin”. Given the overlap in phenotype of some γδ T-cell and NK neoplasms (CD5-, CD56+, βF1-), the lack of complete lineage specificity of γδ T-cell receptor (TCR) gene rearrangement and the limited use of paraffin-section reactive antibodies for γδ T-cells, the proportion and characteristic features of ENKTL of γδ T-cell origin is unknown.
Design: In order to assess the frequency and characteristic features of ENKTL of αβ and γδ T-cell origin, staining for TCRγ chain constant region (gamma3.20, Endogen, Rockford, IL) was performed on 3 TMAs that included 37 ENKTL from Thailand plus controls. All cases were stained for CD3, CD5, CD56, TIA1, βF1, EBER for EBV and many for CD20, CD4, CD8, CD30 and LMP1. Basic clinical and pathologic features were also reviewed. 4 cases with inevaluable TCRγ or βF1 stains were excluded.
Results: All cases tested were CD20- (27/27), EBER+, TIA1+. 4/33 cases were TCRγ+ including one that co-expressed βF1. They were CD3+, CD5- (3/3), CD56+ (2/4), CD4- (3/3), CD8- (2/3), granzyme B+ (2/2), CD30+ (2/3), and LMP1+ (1/1). One TCRγ-, βF1+ case was CD3+, CD5+, CD56-, CD4+, CD8-, granzyme B+, and CD30-. The remaining 28 cases were TCRγ-, βF1-. They were CD3+ (27/28, 96%), CD5- (28/28, 100%), CD56+ (23/27, 85%), CD4- (16/16, 100%), CD8- (16/16, 100%), granzyme B+ (11/13, 85%), CD30+ (10/15, 67%), and LMP1- (4/7, 57%). Comparison of basic clinical and pathologic features showed a female predominance in the TCRγ+ cases, unlike the TCRγ-, βF1- cases (p<0.04, Fisher's exact test).

Basic clinicopathologic features of ENKTL
 TCR expression in ENKTL
Number of patients4128
Age, median (range), yrs45.5 (34-55)2747 (22-80)
Sex, M:F ratio1:30:14.6:1
- Nasal cavity± other3 (75%)1 (100%)19 (68%)
- Other upper aerodigestive tract--5 (18%)
- GI tract1 (25%)-3 (11%)
- Subcutaneous fat--1 (3%)

Conclusions: Among the small proportion of ENKTL of T-cell type, most are of γδ origin. Rarely they may express both γδ and αβ TCR proteins. The γδ T-cell cases are easily confused with cases of NK origin because of their similar phenotype. They appear to occur more frequently in females but otherwise are similar to the presumptive NK cases.
Category: Hematopathology

Tuesday, March 1, 2011 9:30 AM

Poster Session III # 224, Tuesday Morning


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