Adult-Onset Epstein-Barr Virus-Associated T-Cell Lymphoproliferative Disease with Central Nervous System Involvement.

Epstein-Barr virus (EBV)-associated T-cell lymphoproliferative disease (EBV+ T-cell LPD), including chronic active Epstein-Barr virus (CAEBV) disease, can affect the central nervous system (CNS) in children, albeit rarely reported in adults. We report a case of an adult with EBV+ T-cell LPD and CNS involvement treated with haploidentical stem cell transplantation (haplo-SCT) and post-transplant cyclophosphamide (PTCy). A 59-year-old woman developed a high fever and elevated lactate dehydrogenase (LDH) levels. Based on the clinical course, high serum EBV-DNA levels, and the presence of EBV-infected T cells in her bone marrow, she was diagnosed with EBV+ T-cell LPD. The patient initially responded to cooling therapy and chemotherapy, leading to a marked decrease in EBV-DNA levels. Subsequently, she experienced a relapse in the CNS, as evidenced by elevated EBV-DNA levels in the cerebrospinal fluid. After chemotherapy and whole-brain irradiation, the patient underwent haplo-SCT with PTCy, following reduced-intensity conditioning. The EBV-DNA load was undetectable 27 days after haplo-SCT, and MRI findings showed no apparent residual disease. This case highlights the importance of considering CNS relapse despite apparent virologic response in adult-onset EBV+ T-cell LPD. To our knowledge, this is among the few reported adult cases with clinically diagnosed CNS involvement successfully treated with allogeneic SCT.