A 20year female patient with 6th cranial nerve palsy on T2 weighted MRI shows a hyperintense lesion in cavernous sinus which shows homogenous contrast enhancement. Most probable diagnosis is?
Schwannoma [Ref:- Osborn Neuroradiology lle p501; CT and MRI of the Whole Body 4/e p162, 166; Common tumors within cavernous sinus are: Schwannoma, Meningioma and Metastasis. (Ref: Osborn Neuroradiology) Cavernous sinus hemangioma is a very rare tumor of this region. ( All the cavernous sinus tumors can cause sixth nerve palsy (and proptosis). So the diagnosis is to be made on the basis of incidence and MR chaaracterstics. MR characteristics: Menigioma - Usually hypointense to isointense on TI-weighted and isointense to hyperintense with T2-weighted images. - Somebooks write that it is mostly isointense on T2 wt sequences. - Enhances homogenously on post contrast scans. Schwannoma - Mostly hypointense on T1 and hyperintense on T2. - Smaller tumors show homogenous density and strong homogenous enhancement. Larger tumors demonstrate heterogeneity of both density and contrast enhancement because of the presence of intratumoral cystic degeneration & xanthomatous changes. Cavernous hemangioma - Mostly hypointense on T1 and hyperintense on 72. - Shows good homogenous contrast enhancement. Thus meningioma can be ruled out as it usually isointense on T2. We are left with Schwannoma and Cavernous hemangioma. We would personally like to go with Schwannoma as it is one of the commonest tumors of the cavernous sinus and smaller tumors have homogenous enhancement. Cavernous hemangioma though matches more with the contrast enhancement characteristics, is a very rare tumor of this region.
schwannoma
meningioma
cavernous sinus hemangioma
astrocytoma