Clinicopathologic Spectrum of Pediatric Posttransplant Lymphoproliferative Diseases Following Solid Organ Transplant

Context.—Posttransplant lymphoproliferative disorder (PTLD) remains a significant complication in pediatric patients undergoing solid organ transplant (SOT). The majority involve Epstein-Barr virus (EBV)–driven CD20^þ B-cell proliferations, which respond to reduction of immunosuppression and anti-CD20–directed immunotherapy. Owing to the low overall incidence, prospective studies of pediatric PTLD are scarce, leading to a lack of comprehensive understanding of this disorder in pediatric populations. This review aims to bridge this knowledge gap by providing a comprehensive analysis of the clinical, morphologic, and molecular genetic features of PTLD in children, adolescents, and young adults after SOT. Objective.—To examine the clinical features, pathogenesis, and classification of pediatric PTLDs after SOT. Data Sources.—Personal experiences and published works in PubMed. Conclusions.—PTLD includes a broad and heterogeneous spectrum of disorders, ranging from nonmalignant lymphoproliferations to lymphomas. While most pediatric PTLDs are EBV^þ, an increasing number of EBV^– PTLDs have been recognized. The pathologic classification of PTLDs has evolved in recent decades, reflecting advancements in understanding the underlying pathobiology. Nevertheless, there remains a great need for further research to elucidate the biology, identify patients at higher risk for aggressive disease, and establish optimal treatment strategies for relapsed/ refractory disease.