Progressive multifocal leukoencephalopathy, the role of the susceptibility-weighted imaging sequence in a case of immunosuppression of an initially unknown cause.

We describe the case of a 47-year-old woman who was confused and complained about left-sided weakness when she presented to our institution. The patient underwent a head computed tomography that raised the suspicion of a recent-onset ischemic episode (subacute phase). The patient was admitted to the neurology department and underwent a magnetic resonance imaging (MRI) with contrast medium administration. The clinical and laboratory findings and the MRI features, particularly the presence of a hypointense rim in the susceptibility-weighted imaging (SWI) sequences, were consistent with a diagnosis of progressive multifocal leukoencephalopathy (PML). Immunosuppression was observed as a result of lymphopenia, and the patient was subsequently diagnosed with previously undocumented AIDS. Our aim is to present this rare case of PML in an immunocompromised patient with AIDS, describing the main MRI features and the possible role of SWI sequences.