Atypical radiological presentation of progressive multifocal leukoencephalopathy following liver transplantation.

Progressive multifocal leukoencephalopathy (PML), a demyelinating disease of the brain caused by JC virus (JCV), occurs following transplantation and other conditions associated with immunosuppression. On magnetic resonance imaging (MRI), PML lesions typically appear as hyperintense signal on T2-weighted and FLAIR images located in the subcortical white matter, which are devoid of contrast enhancement or mass effect. The prognosis is poor, but unusual inflammatory forms of PML characterized by contrast enhancement have been associated with a cellular immune response against JCV and a better prognosis. The authors report an atypical presentation of PML with contrast-enhancing lesions and mass effect on the MRI in a liver transplant recipient,who had a progressive course and fatal outcome.