Characterization of T-/natural killer cell lymphoproliferative neoplasms associated with systemic, chronic, active Epstein-Barr virus in adults: A report of 5 cases in a Western population

Objectives: Because of its low frequency in adult populations and clinical and laboratory overlap with hemophagocytic lymphohistiocytosis and other T-cell lymphomas, T-cell/natural killer (NK) cell systemic, chronic, active Epstein-Barr virus (EBV) (T/NK sCAEBV) infection remains underdiagnosed, preventing critical, prompt therapeutic interventions. Methods: We report a 5-case series that included 2 adult patients with T/NK sCAEBV and 3 additional adult patients with T/NK lymphomas with concomitant systemic EBV infection to review these entities' overlapping diagnostic and clinical features. Results: Approximately 95% of the world population has been infected with EBV during their lifetime, and infection is usually asymptomatic, with symptomatic cases eventually resolving spontaneously. A small subset of immunocompetent patients develops CAEBV, a life-threatening complication resulting from EBV-infected T-cell or NK cell neoplastic lymphocytes. The sites of end-organ damage in T/NK sCAEBV demonstrate pathologic findings such as reactive lymphoid proliferations, making the diagnosis difficult to establish, with the only curative option being an allogeneic hematopoietic stem cell transplant. Conclusions: This diagnosis is most prevalent in Asia, with few cases reported in Western countries. Adult age is an independent risk factor for poor outcomes, and most cases are diagnosed in pediatric populations.