S8C37P23-1: A cross-section of a portion of the temporal artery is represented. The lumen is narrowed. The intima shows fibro-muscular hyperplasia. To the right in the area identified by blue arrows, the internal elastic lamina is represented; focally, it is duplicated. The internal elastic lamina defines the boundary between the hyperplastic intima and the media of this muscular artery. Just beyond the lower blue arrow, the internal elastic lamina is not represented; from this point to the left of the field, the zone between media and intima is devoid of elastica. It is marked by fibrous tissue. A portion of the media that abuts upon the boundary, especially to the left, shows degenerative changes with shrinkage and pyknosis of nuclei; lymphoid infiltrates also are represented in this area. The defect in the elastic lamina is evidence of elastolysis; it is a feature often seen in older lesions of temporal (giant cell) arteritis.

S8C37P23-2: The internal elastic lamina is reduplicated and portions are coiled. In the area of the green arrows, internal elastic lamina is faintly identifiable; to the left of this area, it is difficult to follow the elastic lamina in continuity from the remnant on the right. A zone of vascularized, inflamed fibrous tissue has formed at the boundary between the intima and media. The inflammation is concentrated in the area primarily affected in lesions of giant cell arteritis. Blue arrows identify the external elastic lamina.

S8C37P23-3: A thickened, fibro-muscular intima is represented to the right and above. The media is represented to the left and below. In the area marked with blue arrows, the internal elastic lamina is fragmented. Along the plane defined by the arrows, and proceeding to the left, the elastic is interrupted (about mid-field). Beyond this point, infiltrates of lymphoid cells have obscured portions of the media and the intima. A few neutrophils also are represented.

S8C37P23-4: In this field, at the interface between media and intima, an ill-defined granuloma interrupts a reduplicated elastic lamina. The granulomatous component, in combination with the other changes, is diagnositic of giant cell arteritis, even in the absence of giant cells.