Non-cutaneous extranodal mature T- and natural killer (NK)-cell neoplasms: clinicopathologic features, genetics and updates

Abstract

Non-cutaneous extranodal mature T- and natural killer (NK)-cell neoplasms represent a broad spectrum of neoplasms involving various extranodal sites, predominantly in the liver, spleen, bone marrow, gastrointestinal tract, and nasal cavity, ranging from indolent to highly aggressive diseases. Extranodal NK/T-cell lymphoma (ENKTL), aggressive NK-cell leukaemia (ANKL), and EBV-positive T-cell and NK-cell lymphoid proliferations and lymphomas of childhood, are strongly associated with Epstein-Barr virus (EBV). Overlapping clinical and histopathological features exist between entities, making differentiation challenging. A multidisciplinary approach is essential in establishing the correct diagnosis. Recent advances in genomics have provided new insights into the pathogenesis, aided in the diagnosis, prognostication, and identification of potential therapeutic targets. This article focuses on the clinicopathologic features of these entities, incorporating recent advances in genetic characterization, and highlighting features that assist in distinguishing these conditions from potential mimickers.