Infratentorial progressive multifocal leukoencephalopathy in a patient treated with fludarabine and rituximab

Progressive multifocal leukoencephalopathy (PML) is a rare demyelinating disease of the central nervous system caused by the JC papovavirus, and is a well known complication in patients with lymphoproliferative diseases (LPDs) during chemotherapy. We report the case of a 59-year-old woman affected by B-cell LPD who underwent three cycles of chemotherapy with fludarabine and rituximab and developed atypical PML six months after the last cycle of chemotherapy. Our patient showed the following peculiarities: chemotherapy regimen was neither heavy nor prolonged; the onset of neurological symptoms was unexpectedly late; the MRI lesion was atypical for non-HIV-related PML, being monofocal and infratentorial with early gadolinium (Gd) enhancement and mass effect; survival was rather prolonged despite the lack of treatment. These data suggest that in patients with LPDs, the occurrence of progressive neurological deficits should induce the suspicion of PML even when clinical onset is late (with respect to chemotherapy) and in the presence of a single infratentorial lesion, with Gd enhancement and mass effect.