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.