We read with interest the series of Type II enteropathy-associated T-cell lymphoma (EATL) by Tse et al. . As this is a rare disease that is more commonly encountered in Asia, such an attempt to assemble cases from the region in order to define its clinicopathological features is laudable. Nevertheless, we would express some concern over the inclusion of three cases with extensive EBV encoded RNA (EBER) expression in the study. These cases were included because they were morphological mimics of Type II EATL, lacked angiocentricity, and showed clonal rearrangement of TCR gene. Similar cases have been documented to be of T-cell lineage by double labeling and T-cell clonality study . In addition, the lack of features such as angiocentricity and necrosis does not exclude extranodal NK/T-cell lymphoma (ENKL) and this neoplasm may also include cases of both NK and T-cell origins [3, 4]. EBER-positivity is characteristic of ENKL, both in cases with NK-lineage (the majority of cases) or T-cell lineage (around 10% of cases, but up to 27% has been reported) . In contrast, the overwhelming majority of Type II EATL has been shown to be EBER− [6–8] and isolated EBER+ cells in this neoplasm are in fact EBV-infected B-cells (Fig. 1). Type II EATL is a newly recognized entity that needs to be properly defined and understanding of this disease is being accumulated gradually with increasing experience. It would be prudent to keep this entity pure at this stage and limit it to EBER− cases. The occasional EBER+ cases can be incorporated at a later stage when more evidence emerges to support its inclusion.
Soo-Yong Tan*, Shigeo Nakamura, Hwan-Cheong Tan*, Yan-hui Liu, Shih-Sung Chuang§, * Department of Pathology, Singapore General Hospital, Singapore, Department of Pathology and Laboratory Medicine, Nagoya University Hospital, Nagoya, Japan, Department of Pathology, Guangdong General Hospital, Guangzhou, China, § Department of Pathology, Chi-Mei Medical Center, Tainan and Taipei Medical University, Taipei, Taiwan.