EBV-Driven NK/T-Cell Lymphoproliferative Disorders: Clinical Diversity and Molecular Insights

The World Health Organization (WHO) and International Consensus Classification (ICC) systems have classified EBV-positive NK/T-cell neoplasms in adults and EBV-positive T/NK-cell lymphoid lymphoproliferative disorders (LPD) in children. Recent molecular profiling techniques have revealed the pathogenesis of these disorders, showing interactions among EBV-encoded proteins, host immune responses, and genetic alterations. Extranodal NK/T-cell lymphoma (ENKTL) shows molecular diversity, with various subtypes (TSIM, MB, and HEA) identified through a multiomics approach. Aggressive NK-cell leukemia (ANKL) has mutations in JAK/STAT, epigenetic regulators, and TP53 pathways. EBV-positive nodal T- and NK-cell lymphoma (ENTNKL) is a new entity, distinguished by primary nodal presentation and a unique molecular profile. Severe mosquito bite allergy (SMBA), hydroa vacciniforme lymphoproliferative disorder (HVLPD), and systemic chronic active EBV disease (CAEBV) are rare childhood EBV-driven LPDs defined by clinico-pathologic criteria, with largely unexplored genomic landscapes. Studies of CAEBV samples have found ENKTL-like driver mutations, including DDX3X and KMT2D, in EBV-infected NK/T cells, while KMT2D and chromatin modifier mutations were common in HVLPD. Comprehensive molecular sequencing of SMBA and Systemic EBV-positive T-cell lymphoma of childhood remains lacking. These findings suggest all EBV+ NK/T-cell LPDs exist on a biological continuum of viral oncogenesis. The integration of clinical, pathological, and molecular information aims to create a more accurate classification system, enabling better risk evaluation and tailored treatment strategies for patients with these complex disorders.