EBV-Driven Lymphoproliferative Disorders and Lymphomas of the Gastrointestinal Tract: A Spectrum of Entities with a Common Denominator (Part 3)

Simple Summary The Epstein-Barr virus (EBV) is a commonly occurring virus, infecting more than 90% of the world population, often early in life. However, only a minority of individuals develop EBV-driven diseases at some point in their lifetime. EBV is associated with several neoplasms including epithelial, mesenchymal and lymphoid tumors. EBV-driven lymphoid proliferations encompass a wide spectrum of diseases with different biological behaviors, developing frequently, although not always, in conditions of immunosuppression. The diagnosis is often complicated and requires a strict combination of clinical, pathological and molecular findings. The aim of this review, divided into three parts, is to provide an update on EBV-driven lymphoproliferative disorders arising in the gastrointestinal tract. In this review, we discuss the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders. EBV is the first known oncogenic virus involved in the development of several tumors. The majority of the global population are infected with the virus early in life and the virus persists throughout life, in a latent stage, and usually within B lymphocytes. Despite the worldwide diffusion of EBV infection, EBV-associated diseases develop in only in a small subset of individuals often when conditions of immunosuppression disrupt the balance between the infection and host immune system. EBV-driven lymphoid proliferations are either of B-cell or T/NK-cell origin, and range from disorders with an indolent behavior to aggressive lymphomas. In this review, which is divided in three parts, we provide an update of EBV-associated lymphoid disorders developing in the gastrointestinal tract, often representing a challenging diagnostic and therapeutic issue. Our aim is to provide a practical diagnostic approach to clinicians and pathologists who face this complex spectrum of disorders in their daily practice. In this part of the review, the chronic active EBV infection of T-cell and NK-cell type, its systemic form; extranodal NK/T-cell lymphoma, nasal type and post-transplant lymphoproliferative disorders are discussed.