Spontaneous recovery from progressive multifocal leukoencephalopathy in a patient with non-active sarcoidosis

We report the case of a 50-year-old female patient with non-active sarcoidosis and no kind of immunosuppression, admitted to our hospital because of increasing confusion and focal neurological deficits. Initially a tumor, herpes encephalitis, or neurosarcoidosis were suspected, but surprisingly biopsy revealed progressive multifocal leukoencephalopathy, additionally confirmed by JC-positive PCR in cerebrospinal fluid. Cases of sarcoidosis and progressive multifocal leukoencephalopathy have been reported before. This is the first case of a patient with no sign of active sarcoidosis and without immunosuppressive therapy who recovered spontaneously with a follow-up time of nearly 3 years.