Does the histopathologic description of Takayasu Arteritis vary from Giant Cell Arteritis?
Yes, but not by much. The histologic appearance of TA is a focal panarteritis very similar to GCA, including “skip lesions” and patchy involvement. Granulomatous inflammation can occur.
One point that distinguishes TA from GCA is that the cellular infiltrate in TA tends to localize in the adventitia and outer parts of the media (including the vasa vasorum), whereas the inflammation of GCA concentrates around the inner half of the media. Additionally, mononuclear cells in the vessel walls of TA patients are mostly gamma-delta T lymphocytes, natural killer cells, and CD8+ T cells rather than the Th1/Th17 T-lymphocytes seen in GCA patients.
