Progressive multifocal encephalopathy after cyclophosphamide in granulomatosis with polyangiitis (Wegener) patients: case report and review of literature.

Progressive multifocal encephalopathy (PML) is a rare demyelinating disorder targeting the central nervous system and resulting from JC virus reactivation. PML occurs in patients immunocompromised because of haematological malignancies, HIV infection or treatment with cytotoxic drugs. Herein, we describe PML occurring in 2 granulomatosis with polyangiitis (Wegener) patients treated with steroids and cyclophosphamide. The outcome was progressively favourable after immunosuppressant discontinuation for 1 patient and fatal for the other. Four previously reported GPA patients developed PML in the course of their disease. One of them improved gradually after immunosuppressant withdrawal. PML should be strongly suspected whenever unusual central neurological manifestations appear in this context. No effective treatment is available, but immunosuppressants should be discontinued if possible.