Neuropathological features of adult-onset neuronal intranuclear inclusion disease with fluid-attenuated inversion recovery high-intensity signals in the cerebellar paravermal area from an early stage: A case report.

Neuronal intranuclear inclusion disease (NIID) is a neurological disorder characterized by eosinophilic intranuclear inclusions (INI) in systemic organs and various cell types. High-intensity signals along the corticomedullary junction on diffusion-weighted imaging and presence of cellular p62-INI in skin biopsy are known indicators for NIID. Furthermore, GGC repeat expansion in NOTCH2NLC is a characteristic genetic alteration in patients with NIID. This report presents the clinical and detailed pathological features of a male older adult with NIID. We also confirmed the presence of fluid-attenuated inversion recovery high-intensity signals in the cerebellar paravermal area, showing similar pathological changes in high-intensity signals along the corticomedullary junction on diffusion-weighted imaging.