Background Giant cell arteritis (GCA) is a vasculitis that involves large and medium sized arteries in patients older than 50 years. Temporal artery biopsy (TAB) is the gold standard for the diagnosis of GCA. Cranial symptoms are the most common manifestations of the disease, while permanent visual loss is the most feared ischaemic complication of GCA and is reported in 10-20% of patients. Previous study have tried to correlate histological features of TAB with cranial and visual symptoms, but the results reported are not conclusive.
Objectives To correlate histological findings of TAB with clinical manifestations in a large single center cohort of consecutive patients with biopsy-proven GCA.
Methods A pathologist with expertise in vasculitis and blinded to clinical data and final diagnosis reviewed all TABs performed for suspected GCA at our hospital between January 1986 and December 2012. Positive TABs showing only small vessel vasculitis and/or vasa vasorum vasculitis without transmural inflammation were excluded from the comparison analysis. Histopathologic features evaluated were: the severity of inflammation and intimal hyperplasia, both graded on a semiquantitative scale (mild=1, moderate=2 severe=3), the presence of intraluminal acute thrombosis, calcifications, giant cells, fibrinoid necrosis and laminar necrosis, consisting in a band of coagulative necrosis sometimes bordered by palisading histiocytes and following the internal elastic lamina.
Results 271 patients had a final diagnosis of biopsy-proven GCA and were included in the study. More severe inflammation on semiquantitative scale was more frequently seen in patients with any cranial symptoms (88.4% grade 3; 87.5% grade 2 and 74.7% grade 1, p=0.026), headache (80.4% grade 3; 80% grade 2 and 65.3% grade 1, p=0.038), abnormalities of TA at physical examination (82.6% grade 3; 63.5% grade 2 and 56.9% grade 1, p=0.001) and halo at TA colour duplex sonography (CDS) (75.5% grade 3; 78.4% grade 2 and 48.5% grade 1, p=0.011). The presence of laminar necrosis was more frequent in patients with visual symptoms (43.1% vs 24.8%, p=0.005), and in those with abnormalities of TA at physical examination (82.3% vs 65.3%, p=0.012). The presence of calcifications was more frequent in patients with visual symptoms (45.5% vs 25%, p=0.003), and in patients without systemic symptoms (71.3% vs 52.7%, p=0.009). More severe intimal hyperplasia on semiquantitative scale was less frequently seen in patients with polymyalgia rheumatica (PMR) (32.2% grade 3; 53.8% grade 2 and 56.3% grade 1, p=0.008). The presence of giant cells was more frequent in patients with jaw claudication (49.2% vs 30.8%, p=0.006). Fibrinoid necrosis was present only in 2 cases (0,7%), in both sparing the temporal artery and limited to a small branch.
Conclusions The data of this large monocentric cohort of biopsy-proven GCA patients evidenced that visual symptoms correlate with the presence of laminar necrosis and calcifications. Cranial symptoms and halo at TA CDS correlate with the severity of mural inflammation. PMR inversely correlates with intimal hyperplasia. Fibrinoid necrosis was not a features of GCA.
Disclosure of Interest None declared