Case of the Week

Sarcoidosis is an idiopathic, chronic, multisystemic, granulomatous disease (noncaseating granulomas).

African Americans and women are at a higher risk (3x and 2x, respectively).

Lesions can affect the lungs, lymphatic system, eyes, skin, liver, spleen, salivary glands, heart, nervous system, muscles, and bones.

Clinical neurologic symptoms occur in approximately 5% of patients. 

 

Neurosarcoidosis can involve any part of the CNS, with various nonspecific clinical symptoms such as headache, cranial nerve deficits, weakness, seizure, diabetes insipidus, hypopituitarism, encephalopathy, or myelopathy.

Large spectrum of anomalies can be found on MRI

Leptomeningeal involvement, nodular and/or diffuse, with preferential involvement of basal cisterns; may spread along perivascular spaces (granulomas can coalesce to form masslike lesions, mainly in the region of the chiasma, floor of the third ventricle, and pituitary stalk)

Cranial nerve thickening and enhancement (most common: nerve VII, II, and V)

Nonenhancing T2-hyperintense brain parenchymal lesion (which can mimic demyelinating disorders)

Enhancing brain parenchymal lesion (mostly affects hypothalamus, brain stem, cerebral and cerebellar hemispheres)

Dural involvement including thickening or mass (main differential: meningioma)

Hydrocephalus (either obstructive due to aqueduct stenosis or communicating with granulomatous infiltration into the subependymal layers and choroid plexus of the ventricular system) 

Spinal cord or nerve root lesions (rare)

Symptoms usually improve after corticosteroid treatment.

This case shows a small granuloma causing aqueduct stenosis with obstructive hydrocephalus. The association with a thickened infundibulum and hypermetabolic mediastinal-hilar lymph nodes is in keeping with neurosarcoidosis. Diagnosis was confirmed with lymph node biopsy by mediastinoscopy demonstrating granulomatous inflammation with noncaseating epithelioid and giant cell granulomas. Patient improved after corticosteroid treatment.

 

Mostly depends on the imaging presentation

Leptomeningeal enhancement: infectious meningitis, tuberculosis, lymphomatous meningitis, meningeal carcinomatosis

Thick infundibular stalk: histiocytosis, lymphocytic hypophysitis, meningitis, germinoma

Aqueduct stenosis: congenital malformation, aqueductal membranous stenosis (postinfectious, post-SAH)