Giant Cell Arteritis: Does Perivascular Inflammation on Biopsy Lead to Clinical Disease?

Background and Objective: Transmural inflammation of the temporal artery on biopsy is considered strongly suggestive of giant cell arteritis (GCA). Occasionally other inflammation patterns are seen. It is controversial whether these findings predict GCA-like disease. Our objective was to describe the clinicopathologic features in a cohort of patients with temporal artery biopsies to examine outcomes of patients with non-transmural inflammation.

Methods: We examined through retrospective chart review the clinical course from 2010-2020 of patients with temporal artery biopsies from 2010-2012. Biopsy results were divided into 3 groups: GCA transmural inflammation, non-GCA perivascular inflammation and negative. Non-GCA perivascular inflammation included small vessel, vasa vasorum and adventitial inflammation. Endpoints included constitutional and craniofacial symptoms, CRP and ESR levels, ASCVD, large vessel complications, and length of steroid treatment.

Results: 95 patients were included. Transmural patients had more visual loss compared with perivascular patients (55.5% vs 15.7%, p=0.004). Transmural patients had more jaw claudication or headache/jaw claudication compared with perivascular patients (44.5% vs 12.6%, p=0.01). Weight loss was more common in transmural patients compared with perivascular (27.8% vs 3.1%, p=0.02). Night sweats, PMR symptoms, and temporal artery tenderness were similar between groups. CRP was higher in transmural patients though not significantly. ESR levels were similar between groups. Transmural patients had a longer steroid duration with a median of 24 months vs 1.5 for perivascular, p=0.001.

Conclusion: Patients with non-transmural inflammation on temporal artery biopsies had improved outcomes when compared with transmural patients. This raises the question of whether steroids should be continued after a biopsy returns with perivascular inflammation.