Unusual cranial nerve palsy caused by cavernous sinus aneurysms. Clinical and anatomical considerations reviewed

Two cases of intracavernous internal carotid artery aneurysm with unusual clinical findings are reported. The pathomechanism and clinical significance are discussed.

The first patient was a 49-year-old woman who presented with 6th nerve palsy and Horner's syndrome caused by a posteriorly located intracavernous aneurysm. The symptoms improved gradually in proportion to the size of the aneurysm. The second patient was a 69-year-old woman with isolated oculomotor superior division palsy caused by an anteriorly located large aneurysm.

In the first case, a local aneurysmal compression at both the 6th nerve and the sympathetic fibers sent from the plexus on the intracavernous internal carotid artery is the most probable explanation. In the second case, the aneurysm might have selectively compressed the superior division of the oculomotor nerve at the anterior cavernous sinus. Clinical recognition of these syndromes results in a better diagnostic orientation. The authors discuss the pertinent anatomy and pathophysiology of the lesions because these findings are rarely seen clinically or in the literature.