This is a 42 year old black male who presents complaining of
periorbital/maxillary numbness and pain for the last 8 months.
T2 as well as post contrast T1 weighted images are provided for
review. Images reveal an enhancing mass that is centered along the
floor of the left middle cranial fossa. There is extension into the
pterygopalatine fissure, orbital apex, as well as the infratemporal
and anterior cranial fossae. The mass is of low signal intensity on
T2 weighted images and there is surrounding mass effect.
CNS sarcoid occurs in approximately 1-8% of people with known
sarcoidosis, although the number has been shown to be as high as
15% at autopsy. Primary CNS involvement is rare. As in other areas,
this is an inflammatory disorder characterized by non caseating
granulomas. Most often, the appearance is that of diffuse meningeal
enhancement, but can also cause meningeal nodules or as a single
intracerebral mass. (as in this case) The meninges and cranial
nerves are affected much more commonly than the brain. Classic MRI
findings include isointensity to gray matter on T1, hypointensity
on T2 (the result of hypercellularity) and homogenous enhancement
pattern.. Differential diagnosis in this case may include:
metastases, lymphoma, meningioma and sarcoid. The most common
clinical findings in patients with neurosarcoid include: 1. Cranial
neuropathy secondary to granulomatous infiltration &
leptomeningeal fibrosis (50-75%) 2. Aseptic meningitis (20%) 3.
Pituitary and hypothalamic dysfunction (5-10%)
1) Osborn. Diagnostic Neuroradiology. Mosby, Baltimore, 1994. p
377. 2) Dahnert. Radiology Review Manual, 3rd ed. Williams &
Wilkins, Baltimore, 1996. p 239.