A young African American woman presented with progressive left vision loss.  Brain MRI with contrast and perfusion studies were obtained.  The studies showed a dural-based lesion involving the lateral aspect of the left cavernous sinus which extended superiorly and crossed the planum sphenoidale to insinuate itself around the contralateral anterior clinoid process. The lesion was isointense to gray matter on T1WI, dark on T2WI, showed homogeneous gadolinium enhancement and increased rCBV on the perfusion images (see below).  The provisional diagnosis of meningioma was made and the patient scheduled for surgical decompression of left optic canal.

Before surgery, a chest radiograph was obtained and showed bilateral hilar nodularities.  Surgery was postponed and a chest CT confirmed the hilar abnormalities and showed parenchymal abnormalities (see below).  Based on the findings a work up for sarcoidosis was performed and was positive.  The patient received steroids and her vision improved.  Follow-up brain MRI showed the lesion to be smaller.

Sarcoidosis is more common in younger (average age: 35 years) African American women.  Over one half of patients will have neurological complaints, generally longstanding.  In about 10% of patients, sarcoidosis is isolated to the CNS.  The most common symptoms are headaches and cranial nerve palsies (mostly affecting the V, VII, VIII and III).  Approximately 15% of patients have dural disease (which is often accompanied by leptomeningeal involvement).  Dural disease responds well to treatment.  Conversely, intra-axial disease leads to seizures and is more difficult to control.  Angiotensin converting enzyme test is positive in 50% of patients.  The MRI findings on our case are typical of sarcoidosis.  The very low T2 signal can be seen in up 20% of meningiomas (particularly of the fibroblastic or transitional types).  Remember that most meningiomas are isointense to gray matter on T2WI (see below).

Suggested readings:

Chirstoforidis GA, Spickler EM, Recio MV, Mehta BM. MR of CNS sarcoidosis: correlation of imaging features to clinical symptoms and response to treatment. AJNR Am J Neuroradio 1999; 20: 655-669

Shag R. Roberson GH, Cure JK. Correlation of MR imaging findings and clinical manifestations in neurosarcoidosis. AJNR AM J Neurodiol 2009; 30: 953-961

Smith JK, Matheus MG, Castillo M. Imaging manifestations of neurosarcoidosis. AJR 2004; 182: 289-295