Is it possible to diagnose Giant Cell Arteritis without observing giant cells
Yes. Up to 50% of positive biopsies show diffuse lymphocytic infiltrate without the evidence of granulomatous inflammation or giant cells. Even after prolonged glucocorticoid therapy, healed temporal arteritis can still be diagnosed as it is characterized by intimal fibrosis, medial scarring, and eccentric destruction of internal elastic lamina. Indeed, glucocorticoid therapy never completely “normalizes” the affected artery.
Importantly, fragmentation and fraying of the internal elastic lamina is a common feature of aging arteries; therefore, these features alone are not indicative of active or healed arteritis. An inflammatory cell infiltrate, even without giant cells, should be present to some degree to diagnose GCA.
