Interpreting Histopathology Reports of Temporal Artery Biopsies Positive for Giant Cell Arteritis (GCA): A Single-Center Retrospective Study

Abstract

Background: The gold standard for diagnosing giant cell arteritis (GCA) is temporal artery biopsy (TAB). However, specific histopathologic findings on biopsy reports are rarely considered in the context of the patient's clinical presentation. The purpose of this study was to analyze the correlation of specific biopsy findings with the clinical presentation of patients with GCA. Methods: Retrospective chart review of patients with a clinical and histopathologic diagnosis of GCA at a single tertiary care neuro-ophthalmology practice from January 2014 to September 2023. Histopathologic findings on TAB were recorded for each patient, along with clinical history, examination, and treatment. Continuous variables were reported as mean values with standard deviations (SD), while categorical variables were described as percentages. Correlation coefficients with P-values were used to evaluate the relationship between biopsy findings and clinical data. Results: A total of 53 patients were included. TAB specimens ranged in length from 0.6 to 3.4 cm, with a statistically significant correlation coefficient between specimen length and total number of positive findings on the biopsy report. A positive correlation coefficient that approached statistical significance was found between the presence of lymphocytes in the biopsy and permanent vision loss (R = 0.253, P-value 0.054), which occurred in 27 patients. Patients were treated with steroids prebiopsy for an average of 9 days; there was no statistically significant correlation between the duration of steroid treatment and the presence of specific histopathologic findings other than involvement of the intima. Conclusions: The results of this study demonstrate that (1) longer temporal artery biopsy specimens are significantly correlated with a higher number of findings on biopsy reports; (2) the presence of arterial stenosis, eosinophils, and lymphocytes correlated with permanent vision loss or degree of vision loss; and (3) the duration of steroid treatment had a significant inverse correlation with intimal involvement but did not affect other histopathologic findings seen with GCA. This retrospective observational study provides clinicians with an approach to understanding the nuances of the histopathologic findings on their patient's TAB report.