Discrepancy in EBV-DNA load between peripheral blood and cerebrospinal fluid in a patient with isolated CNS post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) is a fatal complication of allogeneic hematopoietic stem cell transplantation (HSCT) that is caused by reactivation of Epstein–Barr virus (EBV). A successful approach, monitoring EBV-DNA load in peripheral blood (PB) accompanied by preemptive rituximab therapy, has recently been reported. Here, we describe a 29-year-old woman who developed isolated central nervous system (CNS) PTLD. She received HSCT against acute myelogenous leukemia from a related human leukocyte antigen-haploidentical donor, following a conditioning regimen that included antithymocyte globulin. Tacrolimus and methylprednisolone were given as prophylaxis for graft-versus-host disease. On day +172, the patient’s consciousness deteriorated. Magnetic resonance imaging showed six ring-enhanced lesions in the cerebral hemispheres. These tumors were diagnosed, via a craniotomy and tumorectomy, as PTLD. EBV-DNA load was elevated in the cerebrospinal fluid (CSF) but not detected in PB. She was treated with whole-brain irradiation and rituximab, and achieved partial remission of the tumors. This case serves as a reminder that vigilance is required regarding the development of isolated CNS PTLD; it is worth examining EBV-DNA replication in CSF for diagnosis even when the EBV-DNA load is negative in PB.