General description

Sarcoidosis is a systemic inflammatory disease with an unknown etiology that can affect individuals across a wide age range. Its clinical manifestations and prognosis vary widely. While the disease typically involves hilar and mediastinal nodes, lungs, eyes, and skin, it can also affect nerves (including the central nervous system), heart, kidneys, musculoskeletal system, and digestive organs.

Clinical manifestations

Typical clinical manifestations of sarcoidosis are nonspecific and may include fever, weight loss, cough, sputum production, blurry vision due to uveitis, cutaneous lesions, abnormal sensations, and skeletal pain.

Neuronal involvement

Sarcoidosis affects various neuronal structures including the meninges, cranial nerves, brain and spinal parenchyma, pituitary gland, peripheral nerves, and muscles. This involvement can lead to a range of neuronal manifestations such as headache, blurry vision, seizure, diplopia, numbness, abnormal sensation, impaired memory, dysphagia, and hypopituitarism.

Radiographic features

Pachymeningeal involvement

In neurosarcoidosis, pachymeningeal involvements, including dural thickening and contrast enhancement, are commonly seen in the posterior cranial fossa.

Leptomeningeal involvement

Leptomeningeal involvement of sarcoidosis is commonly observed in suprasellar and basilar part of frontal lobe. Contrast enhanced T1WI and FLAIR may reveal nodular or smooth thickening of pia mater. Linear enhancement in the spinal pia mater is also commonly observed.

Cranial nerve involvement

Contrast enhancement of cranial nerves is typically observed bilaterally in the optic, trigeminal, oculomotor, facial, and acoustic nerves.

Brain parenchymal lesion

Neurosarcoidosis commonly involves the perivascular space of the brain parenchyma.

Intraparenchymal mass

In neurosarcoidosis, granulomatous lesions are commonly observed. On T1WI, hyperintensity is observed, while on T2WI, hypointensity is noted, reflecting the hypercellularity of the lesion. T2WI may also exhibit hyperintensity in the white matter, resembling demyelinating diseases.

Pituitary and hypothalamic lesion

Occasionally, contrast enhancement of the pituitary stalk and hypothalamus with swelling and thickening can be observed, which may lead to pituitary insufficiency.

Spinal cord involvement

Spinal neurosarcoidosis typically involves the cervical and upper thoracic cord, exhibiting swelling, T2WI hyperintensity, and T1WI hypointensity. Contrast enhanced T1WI shows patchy enhancement in the intraspinal cord.

References

1. Ginat, Daniel T., Gurpreet Dhillon, and Jeevak Almast. "Magnetic resonance imaging of neurosarcoidosis." Journal of Clinical Imaging Science 1 (2011).