Healed or quiescent temporal arteritis versus senescent changes in temporal artery biopsy specimens

Temporal arteritis (TA) is a common idiopathic vasculitis of the elderly. It is controversial whether, in the absence of an active inflammatory process, vessel damage secondary to temporal arteritis is distinguishable from changes secondary to arteriosclerosis. The primary goal of this study was to attempt to differentiate microscopically between healed temporal arteritis and arteriosclerosis, in the absence of active vasculitis. This was a retrospective study in which 47 temporal artery biopsy specimens, done between 1981 and 1997 at University of British Columbia Hospital, were reviewed. As well, temporal arteries harvested from 10 autopsy cases with no clinical evidence of vasculitis were used as controls. Haematoxylin and Eosin and Movat's pentachrome stains were used to assess the degree of intimal thickening, presence or absence of inflammation, type of inflammatory cell(s), the degree of reduplication of elastic lamina, calcification, fibrosis, neovascularisation and gaps or losses in the internal and external elastic lamina. No histological findings were specific for temporal arteritis except the presence of mural inflammation. A high degree of variability existed for all other features assessed, within all groups studied. These results indicate that, in the absence of active inflammation, structural changes in the vessel wall do not allow reliable differentiation between healed or quiescent temporal arteritis and arteriosclerosis. The common practice of performing special stains in all temporal artery biopsy cases does not contribute to the ability to recognise temporal arteritis.