[Myelodysplastic syndrome with cyclosporine A-induced encephalopathy presenting with a mass effect on the right basal ganglia after cord blood transplantation].

An 18-year-old female with myelodysplastic syndrome underwent an allogeneic cord blood transplantation in May 2005. The conditioning regimen consisted of total body irradiation, cytarabine and cyclophosphamide. The day of the cord stem cell transfusion was counted as Day 0. For acute GVHD prophylaxis, cyclosporine A (CsA) and methotrexate were used. Engraftment was achieved on Day 30, acute GVHD grade II developed on Day 45 and treatment with methylprednisolone for acute GVHD was started. On Day 68 the patient had generalized seizures accompanied by loss of consciousness, hypertension and left hemiparesis, and was intubated. A cranial CT scan showed a mass effect on the right basal ganglia, and high signal intensities on the T2-weighted and FLAIR images of a MR examination were detected in the bilateral basal ganglia and posterior lobes, the findings of which were compatible with a brain tumor or infectious disease. Since an increased level of apparent diffusion coefficient (ADC) values on the bilateral basal ganglia was noted, we suspected that vasogenic edema had caused the mass effect. She went into remission immediately after CsA treatment was discontinued. Therefore, this case was diagnosed as atypical reversible posterior leukoencephalopathy syndrome (RPLS) associated with CsA. CsA-induced encephalopathy presenting a mass effect in clinical imaging findings is very rare, and an ADC map may be useful for the diagnosis of RPLS.