Giant Cell Arteritis (Temporal Arteritis; Cranial Arteritis; Horton Disease) By Alexandra Villa-Forte, MD, MPH, Cleveland Clinic Reviewed / Revised Jun 2022 | Modified Sep 2022 View Patient Education Pathophysiology Symptoms and Signs Diagnosis Treatment Key Points Giant cell arteritis involves predominantly the thoracic aorta, large arteries emerging from the aorta in the neck, and extracranial branches of the carotid arteries.