Eyes Wide Open – An Unusual Cause of Progressive Supranuclear Palsy Mimic

Progressive supranuclear palsy (PSP) is a rare neurodegenerative tauopathy with an estimated prevalence of 5–7 per 100,000 persons, typically presenting after the age of 65 years with supranuclear gaze palsy, parkinsonism, pyramidal signs, and cognitive decline. Several secondary conditions may mimic PSP, particularly in younger individuals, including paraneoplastic, infectious, ischemic, and autoimmune disorders. We report a case of a young woman with vertically fixed gaze, parkinsonism, cerebellar signs, and lid retraction, consistent with a PSP-like syndrome, in the context of advanced human immunodeficiency virus (HIV) infection and progressive multifocal leukoencephalopathy (PML) due to JC virus (JCV). This case highlights an uncommon but important infectious cause of PSP mimic and underscores the need for thorough evaluation of atypical presentations in younger patients.