Acute Epstein–Barr virus positive cytotoxic T/Nature Killer cell lymphoid hyperplasia (AEBV+CT/NK-LH) mimicking natural killer/T cell lymphoma

Abstract To describe the clinicopathological features of s even patients with acute Epstein–Barr virus (EBV)-positive cytotoxic T cell/ natural killer lymphoid hyperplasia (AEBV + CT/NK-LH) in the lymphnode, in which initial findings led to a preliminary misdiagnosis of extranodal NK/T cell lymphoma(NKTL). Seven cases in children and young people from China with AEBV + CT/NK-LH were retrospectively analyzed. The patients were healthy prior to illness. Sudden onset occurred in all patients, with high fever as the first symptom followed by lymphadenopathy and hepatosplenomegaly. The disease courses before diagnosis were less than 1.5 months. The majority of lymphocytes in the lesions expressed CD3 and Granzyme B or TIA-1, but not CD5 in all cases. CD56 was expressed in numerous cells in 5 of 7 cases. EBER was detected in medium to large-sized cells (50–100 cells per high-power field) in all cases. TCR gene rearrangement was observed in six cases, among which monoclonal rearrangement was found in four cases. All patients received conservative treatment, but not chemotherapy. Four patients underwent anti-HLH therapy, and the others received anti-inflammatory treatment. All patients survived. All patients underwent long-term clinical observation and follow–up and did not relapse. Therefore, AEBV + CT/NK-LH could elicit malignant features mimicking NK/T cell lymphoma pathologically and benign features mimicking IM clinically. The findings indicated that AEBV + CT/NK-LH should be taken into consideration as a potential diagnosis, thus further clinical information (such as age of onset [whether children and young people], nature of onset [whether sudden], disease course [whether short], symptoms [whether systemic], EBV infection status [whether acute], and lymph node involvement) is needed for accurate diagnosis and prognostic evaluation.