Mucocele involving the anterior clinoid process: MR and CT findings.

We report two patients with surgically proved mucoceles involving the anterior clinoid process. One patient had a mucocele of an Onodi cell and the other had a mucocele isolated to the anterior clinoid process. The MR signal was increased on both T1- and T2-weighted images in the first patient but was isointense on both sequences in the second patient, a finding that resulted in misdiagnosis. The developmental and anatomic features, as well as the diagnostic pitfalls, are discussed.