• Idiopathic systemic granulomatous disease with 5% of patients with sarcoidosis developing symptoms
• Approximately 10% of patients with sarcoidosis will have neuroimaging findings, though not all will be symptomatic

• Epithelioid granulomas without caseation or staining for infectious agents
• Granulomas often incorporate into multinucleated giant cells and lymphocytes

• Symptoms
  • Highly variable
  • Depend on site of involvement
    • Range from hydrocephalus, cranial nerve palsies, endocrinopathies, seizures, and paresthesias to myelopathy
• Age
  • Most commonly presents in the third to fourth decade of life
• Gender
  • Female > male
• Ethnicity
  • Most commonly afflicts African Americans

• General
  • Hydrocephalus and/or pachymeningeal, leptomeningeal, or parenchymal findings
• Modality specific
  • CT
    • Negative in 60% to 70% of patients
  • MRI
    • T1WI
      • Hypointense to isointense areas of the brain compared to adjacent gray matter
    • T2WI
      • Variable, mostly hyperintense
  • Contrast
    • Homogeneous or nodular enhancement within the brain parenchyma
    • Pachymeningeal or leptomeningeal enhancement
    • Thickening of the pituitary gland, infundibulum, or cranial nerves with associated enhancement
• Imaging recommendations
  • MRI with contrast
• Mimic
  • When parenchymal, mimics neoplasm and infection, and when meningeal, classically will involve the basilar cisterns and can be difficult to differentiate from tuberculous meningitis or leptomeningeal tumor spread; more often, there is a combination of findings, including meningeal, cranial nerve, and parenchymal involvement

For more information, please see the corresponding chapter in Radiopaedia.

Contributor: Sean Dodson, MD

DOI: https://doi.org/10.18791/nsatlas.v1.03.02.21