[A case of progressive multifocal leukoencephalopathy with Takayasu arteritis and indolent adult T-cell lymphoma/leukemia].

A 65-year-old man with Takayasu arteritis in a stable condition was admitted to our hospital because of rapid progressive dementia. Brain FLAIR/T2-weighted magnetic resonance images revealed high signal intensity in the diffuse subcortical white matter. John Cunningham virus (JCV) genome in cerebrospinal fluid was detected by polymerase chain reaction. Finally, progressive multifocal leukoencephalopathy was diagnosed definitely by brain biopsy. In addition, the patient was found to be complicated by chronic/smoldering adult T-cell leukemia/lymphoma. The administration of mefloquine with mirtazapine was early started within two months after the onset. However, the combination treatment led to no improvement in symptoms and lesion size. The patient died six months after the onset. Therefore, this case suggested that both of HTLV-I infection and B cell abnormalities due to Takasasu arteritis impaired the therapeutic effect.