Longitudinal orientation of temporal artery biopsy for the diagnosis of giant cell arteritis: A cross-sectional study.

To evaluate the diagnostic yield of a longitudinal temporal artery biopsy (TAB) orientation relative to a transverse orientation for the diagnosis of temporal arteritis. Patients with giant cell arteritis (GCA) from a multicenter prospective cohort study were included in this study. All patients included met the 1990 American College of Rheumatology classification criteria for GCA. Two independent pathologists blind to the relevant clinical data reviewed the TAB specimens. TAB positivity rates were compared between biopsy section orientations (transverse or longitudinal) with adjustment for potential confounding factors. Histological features were compared between orientations. This study included 337 patients with a transverse TAB section (mean age: 74.9 years, 70.6% women) and 69 patients with a longitudinal TAB section (mean age: 75.1 years, 81.4% women). After adjustment for confounding factors, longitudinal TAB section was found to be associated with a higher rate of biopsy positivity (OR: 2.93; 95% CI: 1.07 to 8.04), with 15.0% more positive TAB results. Giant cells, inflammatory cells, nerve inflammation and disruption of the internal elastic lamina were all more frequently observed on longitudinal than on transverse sections. This is the first study to suggest that the use of a longitudinal section for TAB results in a higher diagnostic yield than the transverse orientation.