Progressive multifocal leukoencephalopathy in a patient with Good's syndrome.

Good's syndrome (GS) is an immunodeficiency characterised by thymoma, hypogammaglobulinemia and impaired T-cell function. The clinical symptoms are recurrent or chronic infections from common or opportunistic pathogens and diarrhoea. Encephalitis is rare, mostly associated to cytomegalovirus. We present a 65-year-old woman who developed blindness, motor deficits and cognitive changes over a 4-month period. MRI of the brain showed symmetric subcortical white matter changes in the occipital lobes, first thought to correspond to posterior reversible encephalopathy syndrome. A thymoma was found and operated. The patient had no B cells, low immunoglobulins and an inverted CD4/CD8 ratio. GS was diagnosed. In the cerbrospinal fluid >1 million JC virus copies/mL were found and a repeat MRI now showed a picture compatible with progressive multifocal leucoencephalopathy (PML). Her disease had a fatal outcome. The present case is the second reported association between GS and PML.