A 73-year-old woman received systemic corticosteroids for suspected temporal arteritis after blindness developed in the right eye during the previous day. Because a right temporal artery biopsy specimen was reported as normal, a diagnosis of arteriosclerotic ischemic optic neuropathy was made and the corticosteroid therapy was discontinued. Two weeks later the patient rapidly lost vision in her left eye. A left temporal artery biopsy specimen showed granulomatous arteritis adjacent to normal artery (skip area). Deeper sections of the original right temporal artery biopsy specimen also demonstrated a small focus of granulomatous arteritis adjacent to normal artery. In patients with suspected temporal arteritis, numerous step sections of a long segment of temporal artery should be examined; if the results are normal, the contralateral temporal artery should be studied. A nonspecific inflammatory reaction within or adjacent to the artery should alert the pathologist to the possible presence of a nearby focus of granulomatous arteritis.