[1442] Clinicopathologic Spectrum of Non-Hepatosplenic Gamma-Delta T-Cell Lymphoma: A Review of 19 Cases

JY Song, A Garcia-Herrera, SS Chuang, F Climent, S Pittaluga, M Raffeld, P Gaulard, E Campo, A Martinez, ES Jaffe. National Cancer Institute, Bethesda, MD; Hospital Clinic, University of Barcelona, Barcelona, Spain; Hospital Henri Mondor, Creteil, France; Chi-Mei Medical Center, Taipei Medical University, Taipei, Taiwan

Background: Non-hepatosplenic gamma-delta T-cell lymphomas (GDTL) are rare, and were incorporated in the 2008 WHO classification only as primary cutaneous GDTL. However, the spectrum of the disease and what other anatomic sites may be involved have not been well characterized.
Design: We collected cases from the authors' institutions based on a cytotoxic T-cell phenotype (+CD3 and +TIA-1 or +Granzyme B), lack of βF1 expression, and absence of EBV in all but one case. T-cell receptor gamma gene rearrangement studies were performed by PCR as well as immunohistochemical staining for T-cell receptor delta.
Results: The most common sites involved were the skin/subcutaneous tissue (8/19, 42.11%) and GI tract (5/19, 26.32%) places where normal gamma-delta T-cells are mainly found. Other sites included lymph node (1/19), brain (1/19), orbit (1/19), and lung (1/19). Two cases had multiple sites involved (one involved the skin, liver, lymph node and peripheral blood, while the other involved the skin and stomach). TCR gene rearrangements by PCR showed clonality in 15 of the 17 cases (88.24%) successfully evaluated. TCR delta immunohistochemical staining was positive in 12 of the 19 cases (63.16%) and was positive in two cases that were negative for TCR gamma gene rearrangements by PCR. “Silent” cases (defined as TCR gamma clonal by PCR, but negative for TCR delta and beta by immunohistochemistry) were histologically and immunophenotypically similar, and presented in skin/subcutaneous tissue (3), GI tract (3), and brain (1).
Conclusions: We confirm that the skin/subcutaneous tissue is the most common site for non-hepatosplenic GDTL with the GI tract being the next most common. However, the disease can present in a variety of mainly extranodal sites. A related process may be TCR silent T-cell lymphoma.
Category: Hematopathology

Tuesday, March 23, 2010 9:30 AM

Poster Session III # 200, Tuesday Morning

 

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