Synchronous Aggressive NK Cell Leukemia and EBV-positive T-cell lymphoma in a 30-year old Vietnamese Woman; Case Report and Literature Review

Background: Aggressive NK cell leukemia (ANKL) and systemic EBV-positive T-cell lymphoma of childhood (SEBVTCL) with CD4-positive immunophenotype are both rare. Both entities are associated with prior systemic chronic active EBV disease (CAEBV) and presentation with Hemophagocytic Lymphohistiocytosis (HLH). Whereas ANKL is typically seen in young to middle-aged adults, SEBVTCL is most commonly seen in children and young adults. We report the case of a 30-year-old Vietnamese woman who presented acutely with high fever, generalized lymphadenopathy, hepatosplenomegaly, and HLH, after a months-long history of fever and malaise, more than one year after an acute EBV infection. Methods: : Immunohistochemistry; flow cytometric immunophenotyping; polymerase chain reaction (PCR), Next Generation Sequencing (NGS) Results: : At the time of hospital admission, automated complete blood count (CBC) with differential count showed slight anemia, slight lymphocytosis, and moderate thrombocytopenia. HIV serology was negative. Whole blood PCR for EBV was positive showing 98,000 copies/ml. A lymph node biopsy revealed histology and immunohistochemistry consistent with the WHO-HAEM5 classification of SEBVTCL arising in CAEBV. Blood and bone marrow studies performed for staging revealed no histologic or immunohistochemical evidence of T-cell lymphoma in the bone marrow core, however, atypical blood smear lymphocyte morphology and blood immunophenotyping by flow cytometry were consistent with WHO-HAEM5 classification of ANKL. NGS revealed no evidence of genetic variant(s) associated with HLH in Vietnam. Conclusion: This unusual synchronous presentation of two distinct EBV-driven T/NK cell neoplasms in a Southeast Asian woman highlights the importance of keeping EBV-positive lymphoproliferative disorders in the differential diagnosis for both children and adults, particularly those of Asian and Southeast Asian descent.