Mature T-cell and NK-cell lymphomas in Thailand: an analysis of 71 cases.

ABSTRACT

OBJECTIVE: To identify the distribution of mature T-cell and NK-cell lymphomas in Siriraj Hospital and compare to the other world regions, using the latest WHO classification (2008). MATERIAL AND METHOD: Newly diagnosed cases of such lymphomas between January 1, 2004 and December 31, 2006 at Siriraj Hospital were recruited and reviewed. Additional immunohistochemical studies and/or EBV-encoded RNA (EBER) in situ hybridization were performed from the formalin-fixed paraffin-embedded tissue. Then, lymphomas were reclassified according to the WHO classification (2008). RESULTS: Seventy-one cases including extranodal NK/T-cell lymphoma, nasal type (ENKTL, 31.0%), anaplastic large cell lymphoma (18.3%), angioimmunoblastic T-cell lymphoma (14.1%), peripheral T-cell lymphoma, not otherwise specified (12.7%), mycosis fungoides (MF, 8.5%), subcutaneous panniculitis-like T-cell lymphoma (SPTCL, 7.0%), primary cutaneous anaplastic large cell lymphoma (PCAL, 5.6%), primary cutaneous gamma-delta T-cell lymphoma (PCGDTL, 1.4%), and enteropathy-associated T-cell lymphoma (1.4%) were included in this study. In terms of changing version of the WHO classification from 2001 to 2008, only one case had the diagnosis changed from MF to PCGDTL, a newly proposed entity in the 2008 version. CONCLUSION: ENKTL was the most common in the present series and it had a significantly higher frequency than those reported in other previous studies. The frequency was relatively higher in SPTCL, PCAL, and MF when compared to the other series. Furthermore, changing the WHO classification from the 2001 version to the recently published2008 version may not affect the proportion of NK/T-cell lymphoma.