Abstract
Purpose: :
To establish the important histologic parameters that are helpful in recognizing temporal arteritis in patients who have been treated with steroids prior to obtaining the biopsy specimen, and to analyse the clinical parameters and correlate them with the histopathologic and immunohistochemical findings.
Methods: :
Approximately 1400 cases of temporal artery biopsy specimens are on file in the Ophthalmic Pathology Laboratory at the Cullen Eye institute spanning a 17–year period (1988–2005). Fifteen percent of the cases were positive for giant cell arteritis (GCA). The clinical features were evaluated and correlated with the histopathologic findings. Each case was evaluated with respect to age, sex, race, clinical findings, ESR, CRP, corticosteroid dosage (oral versus IV), and the duration of treatment. The time interval between onset of steroid therapy and obtaining the biopsy was recorded from each patient. In selected cases, histiocytic markers (CD68 and HAM56) were performed to identify the presence of epitheliod histiocytes, which characterizes a granulomatous inflammation.
Results: :
The three most reliable histopathologic parameters of corticosteroid – treated temporal arteritis are the following: 1) foci of epitheloid histiocytes and lymphocytes more frequently located between the outer muscular layer and adventitia, but occasionally they were observed between the muscle layer and intima, 2) large circumferential defects in the elastic lamina (best seen with Movat’s pentachrome), and 3) absent or few multinucleated giant cells. In some cases the main artery appears normal while the primary branches show evidence of a healing arteritis. The histologic findings do not depend on the route of steroid administration (oral versus intravenous).
Conclusions: :
Striking histologic differences were recognized objectively between patients with active (untreated) GCA and patients who have been treated with corticosteroids. The earliest histopathologic changes were detected within the first week following steroid therapy (usually after day 4 to the end of the first week). The histologic findings were more difficult to recognize after two to three months following steroid treatment. A band–like lymphocytic infiltrate between the outer muscle layer and the adventitia was frequently observed and supports the interpretation (as proposed by Weyand and Goronzy) that the adventitia is the center of the immune response in temporal arteritis.
All pathologists reading temporal artery biopsies should be able to recognize this entity.
Keywords: pathology: human • visual impairment: neuro-ophthalmological disease • corticosteroids