Giant Cell Arteritis : Microscopic Features
Microscopic Features: In giant cell arteritis (GCA), inflammatory damage to the vessel wall causes considerable intimal hyperplasia leading to luminal narrowing or obstruction (as shown here). Tunica media may show smooth muscle loss with replacement fibrosis. The histologic changes in GCA are chronic and insidious. If extensive fibrinoid necrosis and thrombosis are present, it is unlikely to be GCA. Inflammatory changes are commonly segmental with skip areas that appear normal. Therefore, exhaustive serial sectioning and submission of the biopsied vessel is necessary. A negative biopsy does not exclude the diagnosis of GCA. Image courtesy of Dr. Ibrahim Zardawi; used with permission.