Spontaneous thrombosis of intracavernous internal carotid artery aneurysm and parent artery occlusion in patients with positive balloon test occlusion--two case reports.

Two patients with giant intracavernous internal carotid artery (ICA) aneurysms were intolerant to balloon test occlusion of the ICA, and later developed spontaneous thrombosis of the aneurysm and the parent ICA without ischemic sequelae. Case 1: A 60-year-old female with a giant right intracavernous ICA aneurysm presented with right abducens nerve paresis. An unsuccessful extracranial-to-intracranial bypass graft operation was complicated by transient postoperative ophthalmoplegia. The patient did not tolerate balloon test occlusion of the right ICA after attempted bypass surgery, and was treated conservatively. The patient presented with acute onset of headache 3 years later. Case 2: A 50-year-old female with a giant right intracavernous ICA aneurysm presented with right abducens nerve paresis. The patient was managed conservatively after a positive balloon test occlusion of the right ICA. The patient suffered transient hypopituitarism and acute onset of headache 2 years later. Spontaneous thrombosis of the aneurysms and occlusion of the parent ICA were found in both patients. Neither had major hemispheric infarcts, but the first patient had asymptomatic infarcts, which were presumed to be thromboembolic in nature. Patients with intracavernous ICA aneurysms who have positive balloon test occlusions appear to develop tolerance to spontaneous and gradual occlusion of the ICA without significant sequelae. However, these patients have an increased risk of developing embolic infarctions. The role for anticoagulation and repeat hemodynamic tests remains unclear.