Can pulmonary sarcoidosis trigger a progressive multifocal leukoencephalopathy? Considerations from a case series and a review of literature

Progressive multifocal leukoencephalopathy (PML) is a severe infectious brain disease with lethal outcome mainly seen in immunocompromised subjects. Herein, we describe a new form of PML with different outcome which was observed in patients suffering from systemic sarcoidosis. Thus, we raise the question whether preexisting sarcoidosis might predispose for or even trigger PML.