Radiological features of internal carotid artery occlusion caused by pituitary apoplexy: illustrative case

BACKGROUND Pituitary apoplexy rarely causes internal carotid artery (ICA) occlusion and acute ischemic stroke. Some cases have been reported, but the neuroimaging findings, including cerebral angiography, have not been discussed. OBSERVATIONS A 55-year-old male suffered the sudden onset of right cervical pain and left mild hemiparesis. Computed tomography indicated a pituitary mass, and magnetic resonance angiography showed a right ICA occlusion. The initial diagnosis was ICA occlusion caused by ICA dissection. His symptoms worsened and the region of cerebral infarction expanded, so the patient was transferred to our hospital. Magnetic resonance imaging and cerebral angiography showed the sudden stoppage of right ICA blood flow caused by local compression of the tumor near the distal dural ring. The diagnosis was acute ischemic stroke resulting from ICA pseudo-occlusion caused by pituitary apoplexy, and emergent endoscopic transsphenoidal resection was performed. Postoperatively, the right ICA was completely patent, and hemiparesis was improved with rehabilitation. LESSONS ICA occlusion caused by pituitary apoplexy is very rare, but emergent treatment is necessary. However, the pathology is difficult to diagnose quickly. Neuroimaging findings showing that the ICA is easily stenosed or occluded if rapidly compressed by the tumor near the distal dural ring may be useful to rapidly diagnose and treat.