Clinicopathological analysis of 12 patients with Epstein–Barr virus-positive primary intestinal T/natural killer-cell lymphoma (EBV⁺ ITNKL)

Aims: Epstein–Barr virus-positive (EBV⁺) intestinal T/natural killer (NK) cell lymphoma (ITNKL) is an uncommon tumour with an extremely aggressive clinical behaviour. However, the clinicopathological characteristics of this tumour, including T cell receptor (TCR) phenotype and the patient's background, remain unknown. The aim of this study was to elucidate the detailed clinicopathological profile of EBV⁺ ITNKL. Methods and results: We enrolled 12 patients with EBV⁺ ITNKL without nasal involvement into the study. All patients were characterized by involvement of the small intestine with concurrent lesions of the large intestine in two patients. Seven patients (58%) had Lugano stages IIE/IV disease and eight (67%) were categorized as high–intermediate/high-risk according to the Prognostic Index for PTCL (PIT). Three patients (25%) with an age of onset of less than 50 years had chronic active EBV infection (CAEBV). Five CD56-positive patients (42%) had a poorer prognosis than those without CD56 expression (P = 0.008). NK cell-type lymphoma defined by the absence of any TCR expression or clonal TCR-γ rearrangement was found in six patients (50%). Interestingly, EBV⁺ intra-epithelial lymphocytosis was observed in one case with a background of CAEBV. Conclusions: This study is the first to shed light on the significant heterogeneity of EBV⁺ ITNKL and its relationship with CAEBV, especially in patients younger than 50 years of age. These observations will provide a guide for diagnostic and therapeutic approaches in routine practice.