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.