S8C38P24-1: In this example of temporal arteritis, the intima is slightly hyperplastic.It is composed of fibromyxoid tissue containing loosely spaced smooth muscle cells. The arteritis is focal (area outlined by green arrows), but transmural. There is a zone of fibrinoid necrosis involving the intima, and extending through the media. Lymphoid cells are clustered near the level of the internal elastic lamina. They are present in the adventitia and have clustered at the interface between the media and the adventitia (i.e., the domain of the external elastic lamina).

S8C38P24-2: In this small branch of the temporal artery, lymphoid infiltrates in the adventitia hug the media. Green arrows identify a small granuloma involving the media and extending to the interface with the intima.

S8C38P24-3: Infiltrates of poorly preserved lymphocytes and histiocytes have collected at the level of the external elastic lamina; a thin layer of smooth muscle cells, immediately adjacent to the infiltrates, shows necrosis. In this area, cytoplasms are more brightly acidophilic and the nuclei of smooth muscle cells are not regularly spaced.