Isolated cerebral manifestation of Epstein-Barr virus-associated post-transplant lymphoproliferative disorder after allogeneic hematopoietic stem cell transplantation: a case of clinical and diagnostic challenges.

We present the case of a 49-year-old male patient with Epstein-Barr virus (EBV)-associated post-transplant lymphoproliferative disorder (PTLD) limited to the brain that occurred 6 months after allogeneic hematopoietic stem cell transplantation (HSCT). Clinical symptoms included mental confusion, ataxia, and diplopia. Magnetic resonance imaging (MRI) revealed cerebellar and periventricular lesions consistent with an inflammatory process. Cerebrospinal fluid (CSF) analysis, but not peripheral blood, was positive for EBV-DNA, but no malignant cells were found. Brain biopsy was not feasible because of low platelet counts. As we considered a diagnosis of either EBV-associated encephalitis or PTLD, the patient was treated with rituximab combined with antiviral therapy. However, the cerebral lesions progressed and follow-up CSF testing revealed immunoglobulin H clonality as evidence of a malignant process. Subsequent treatment attempts included 2 donor lymphocyte infusions (DLI). Despite treatment, the patient died from autopsy-proven PTLD within 8 weeks of the onset of symptoms. This case demonstrates the clinical and diagnostic challenges of primary cerebral PTLD in a patient following allogeneic HSCT.