HIV-Associated JC Virus–Granule-Cell Neuronopathy (JCV–GCN) with the Hot-Cross-Bun Sign

Progressive multifocal leukoencephalopathy (PML) remains an important complication of HIV-1/AIDS, despite widespread combined antiretroviral therapy (cART). As its name implies, it was long thought to be only a demyelinating disease restricted to brain white matter. However, JC virus (JCV), the causative agent of the classic PML form, infects glial cells and neurons, and is now known as the etiology of granule-cell neuronopathy (JCV–GCN), the productive JCV encephalopathy of cortical pyramidal neurons, and productive JCV meningitis of leptomeningeal and choroid plexus cells [1]. Histological studies demonstrated that neurons are infected more frequently than clinically recognized, especially the cerebellar granular layer [2]. Herein, we describe the particular MRI pattern of our JCV–GCN patient to alert physicians to recognize its origin and deal with it appropriately.