Introduction
Post-transplant Lymphoproliferative Disorder (PTLD) encompasses a heterogenous group of conditions with histopathological features, characterized by the abnormal expansion of lymphoid cells, ranging from non-destructive lymphoid hyperplasia to monomorphic proliferation indistinguishable from malignant lymphoma. 1,2,3 PTLD is the most common post-transplant malignancy in children and monomorphic PTLD the largest single entity.4-8 Up to 80% of pediatric PTLD cases have lymphoid expansion driven by Epstein Barr virus (EBV) and immunosuppressive agents, impairing T-cell surveillance, are contributory.1,2,6-15
Treatments employed for PTLD include reduction of immunosuppression (RIS), EBV-specific cytotoxic T-lymphocytes (EBV-CTLs), monoclonal anti-CD20 antibody rituximab, and conventional chemotherapy.15-26 Early or polymorphic lesions are favored to respond to reduction of immunosuppression, EBV-CTLs or rituximab, conversely, monomorphic PTLD often requires a chemotherapy-based approach.16-19,25-30 Treatment protocols for monomorphic PTLD are not standardized and little is known about how providers manage these children. This study sought to describe the characteristics associated with monomorphic PTLD, post-solid organ transplant (SOT), treatment approaches and outcomes at pediatric centers in Canada.