[Toxoplasmosis-associated central nervous system vasculitis accompanied by multiple cerebral hemorrhages developing subsequent to cord blood transplantation].

A 57-year-old man with high-risk myelodysplastic syndrome underwent umbilical cord blood transplantation. He began receiving steroids on day 14 for acute graft-versus-host disease, and experienced dizziness on day 75 during gradual dose reduction. Multiple hemorrhages were observed in the cerebrum, cerebellum, and brainstem. His bleeding increased, and he underwent a brain biopsy on day 91. Subsequently, he was diagnosed with central nervous system vasculitis (CNSV) on the basis of the observed aggregation of mature CD3+ lymphocytes around small vessels and vascular wall invasion by lymphocytes and macrophages. After receiving high-dose steroid therapy, cerebral hemorrhage stopped; however, dysphasia occurred on day 113 and the patient died of cerebral edema on day 128. Toxoplasma DNA and tachyzoites were detected in the brain biopsy specimen during additional examinations; therefore, we suspected that the toxoplasmosis was related to the onset of CNSV. CNSV is a rare, rapidly progressing disease that may present as a fatal post-transplantation central nervous system complication. Investigating the causes of CNSV, including CNSV associated with toxoplasmosis, is critically important for improving the prognosis of patients with CNSV.