JCV granule cell neuronopathy: A rare case manifestation.

Granule cell neuronopathy (GCN) caused by John Cunningham virus (JCV) is a rare yet significant neurological complication, particularly in immunocompromised individuals such as those with AIDS. We present a case of a 34-year-old HIV-positive male exhibiting classical symptoms of cerebellar dysfunction. Magnetic resonance imaging revealed demyelination suggestive of progressive multifocal leukoencephalopathy (PML). Histopathological examination confirmed JCV-GCN, characterized by lytic infection of cerebellar granule cell neurons. Among the 41 reported cases of JCV-GCN, histopathological data were available for only 10 cases. Ours is the 11^th case with available histopathology. This case underscores the importance of considering JCV infection in the differential diagnosis of progressive cerebellar syndromes in immunocompromised patients. Early recognition and diagnosis are crucial for appropriate management and prognosis.