Atypical progressive multifocal leukoencephalopathy in a kidney transplant recipient with improving symptoms after immunocompetence recovery.

Progressive multifocal leukoencephalopathy (PML) is a viral infection due to John Cunningham Virus (JCV) resulting in progressive damage of brain white matter, mostly related to HIV infection or hemato-oncological malignancies. PML onset is usually multifocal with rapid neurological progression and poor prognosis. Here we report an atypical case of PML with monofocal onset and a good outcome in a 64-year-old man who received a kidney transplant for end-stage renal disease (ESRD). The applied antirejection immunosuppressive drug regimen included tacrolimus, prednisone and mycophenolic acid. Three years after the transplant, he complained of right-hand tremor and rapidly progressive right hemiparesis, with prominent involvement of the upper limb. Brain magnetic resonance imaging (MRI) showed a significant demyelinating area in the left frontal lobe, without mass effect and contrast enhancement. Real-time PCR analysis revealed the presence of JCV on cerebrospinal fluid. Consequent immunosuppressive drug suspension resulted in a global improvement of neurological symptoms and a favourable evolution of the neuroradiological findings. Subsequent eight-year follow-up MRI confirmed the stability of imaging findings over time. Therefore, early recognition of PML symptoms and MRI sign along with the rapid suspension of immunosuppressive drugs can modify the natural history of this disease after a kidney transplant.