[Imaging Findings of Sarcoidosis in Neurology]

Sarcoidosis is a systemic granulomatous inflammation of unknown etiology that is reported in all age groups but with a higher prevalence in young adults. Sarcoidosis frequently involves the lungs, eyes, lymph nodes and skin. The involvement of the central nervous system (CNS) is reported with other sarcoidosis forms. Although only nervous system involvement presenting as CNS lesions are seen in 1% of cases, autopsy studies have confirmed CNS lesions in up to 25% of the cases. The nervous system including the brain, spinal cord, cerebral meninges, cranial nerves, pituitary gland, peripheral nerves, and muscles are reported to be affected. Although imaging findings of the nodules in sarcoidosis are nonspecific and atypical in 25-30% of cases, familiarity with the relevant clinical symptoms is helpful in recognizing sarcoidosis presence. The histopathological biopsy results of the organ affected by sarcoidosis help identify the characteristic noncaseating granuloma and its aggregation, and together with the imaging findings often reflecting such microstructure aid in sarcoidosis confirmation. This section describes the characteristic features seen in each image along with the image findings for each site.