Primary central nervous system post-transplant lymphoproliferative disorders

The post-transplant lymphoproliferative disorders (PTLD) are a heterogeneous disease entity of lymphoid and plasmacytic proliferations that can occur after solid organ and bone marrow/stem cell transplantation. PTLD sometimes involves the central nervous system (CNS), but primary occurrence in central nervous system (PCNS-PTLD) is rare. The Epstein-Barr virus (EBV) plays a causative role, and up to 90% of the tumors are associated with this virus. Diagnosing PCNS-PTLD is often challenging based solely on computed tomography, magnetic resonance imaging, and physical findings; therefore, direct biopsy of the lesion is usually necessary to make a definitive diagnosis. The optimal therapy for PCNS-PTLD remains unknown. Dose reduction or discontinuation of immunosuppressive agents is effective for approximately half of PTLD patients, but not for most patients with PCNS-PTLD. It has been noted that CNS involvement is a poor prognostic factor, but early diagnosis and initiation of chemotherapy or radiotherapy seem critical for maximizing the likelihood of a favorable outcome.