Pathology of central nervous system posttransplant lymphoproliferative disorders: lessons from pediatric autopsies.

Posttransplant lymphoproliferative disorders (PTLD) involving the central nervous system (CNS) in children are uncommon and can prove diagnostically challenging. The clinical and imaging characteristics of CNS PTLD can overlap with those of infection, hemorrhage, and primary CNS tumors. Some cases of CNS PTLD remain clinically unsuspected and are diagnosed postmortem. We report 6 instances of CNS PTLD in children, 2 of which were limited to the CNS and were unsuspected before autopsy. In our autopsy series, PTLD was found outside the CNS in 4 out of 6 cases. Since CNS PTLD has a poor prognosis and the presentation can be subtle, unsuspected, and high grade, it is important to maintain a high index of suspicion and to perform imaging and brain biopsy whenever clinically appropriate. In the presence of leptomeningeal involvement, the diagnosis could be made by cerebral spinal fluid examination.