Primary intestinal Epstein⇓Barr virus-associated natural killer/T-cell lymphoproliferative disorder: A disease mimicking inflammatory bowel disease

Abstract

Background and Aims: Primary intestinal Epstein–Barr virus [EBV]-associated natural killer/T-cell lymphoproliferative disorder [PIEBV+ NK/T-LPD] is a rare clinical entity, which is difficult to differentiate from inflammatory bowel disease [IBD]. We present a series of Chinese patients with PIEBV+ NK/T-LPD to increase awareness among clinicians of this condition. Methods: Patients diagnosed with PIEBV+ NK/T-LPD at West China hospital between 2014 and 2016 were included. Clinical and histopathological characteristics were reviewed, and key aspects of differential diagnosis were presented. Results: Twelve patients diagnosed with PIEBV+ NK/T-LPD were identified. Initial symptoms included intermittent fever [11/12 patients], abdominal pain [9/12], haematochezia [8/12], and diarrhoea [3/12]. Main endoscopic findings included multisegmental irregular, variable-sized ulcers, isolated giant ulcers, and diffuse inflammation. Colon and ileocaecum were mainly affected in 11 patients. The main PIEBV+ NK/T-LPD immunophenotypic profile of the infiltrating cells was CD3ε-positive NK/T cells characterised by positiveT-cell intracellular antigen-1 and granzyme B, with CD5 deletion. In situ hybridisation was positive for EBV-encoded small RNAs 1/2 in all patients. Eleven patients were misdiagnosed with ulcerative colitis [4/11], Crohn’s disease [4/11], or tuberculosis [TB, 3/11], owing to the similar endoscopic and histopathological features. The mean number of endoscopic procedures performed before reaching the diagnosis of PIEBV+ NK/T-LPD was 3.58; in four patients, the diagnosis was confirmed only after surgical resection following complications. Conclusions: PIEBV+ NK/T-LPD may be difficult to differentiate from IBD orTB owing to overlapping endoscopic and pathological findings. Early identification of EBV reactivation in tissue samples is essential for the accurate diagnosis.