[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.