A case of enlarged cavernous sinus mistaken for petrous apex tumor.

We experienced a case of abnormally enlarged cavernous sinus extending into the petrous apex, which was confused with a petrous apex tumor or an enlarged Meckel cave. The CT and MR appearances were of expansile lesions in the petrous apex with water signal intensities on both T1- and T2-weighted MR images. Unfortunately, these findings were not specific. Cerebral angiography was only suggestive of enlarged cavernous sinus involving the petrous apex because of opacification of the petrous apex in the venous phase. Our case was confirmed by surgery as enlarged cavernous sinus involving the petrous apex.