Session Title: Vasculitis
Session Type: Abstract Submissions (ACR)
A positive temporal artery biopsy (TAB) with giant cells, active inflammation and intimal hyperplasia is the gold standard test for diagnosing temporal arteritis. However, a negative TAB does not rule out the disease. In this preliminary analysis we have looked at the histological features of the TAB’s assessed in a prospective multicentre study of patients with suspected temporal arteritis (TABUL).
Temporal artery biopsies were performed in all patients with suspected temporal arteritis from June 2010 to December 2013. All biopsies were taken from the symptomatic side and examined by the local pathologist, recording results on a standardised case report form in addition to a routine pathology report. We describe the key histological features in the intima and internal elastic lamina, the presence of inflammatory infiltrates (including giant cells), thrombus, occlusion and recanalisation. Age, sex, median time to biopsy from starting steroids, biopsy length and clinical diagnosis at baseline assessment were recorded.
In this preliminary analysis, data was available from 350 patients (254 female: 86 male, mean age = 71.1±9.5 (SD), [range 47-96]), of whom 348 received steroids. The mean time to biopsy following initiation of steroids was 5±3 (SD) days with 6 GCA biopsy positive cases greater than 10 days. The mean length of the temporal artery biopsy was 11.9±7.4 (SD) mm. Only 332 biopsies consisted of an artery (94.9%), from which 89 cases were positive for GCA (26.8%). Of the 89 cases, 69 had internal hyperplasia and 11 had both internal hyperplasia and arteriosclerosis in the intima. Fragmentation in the internal elastic lamina was reported in 53 cases, 24 cases reported both fragmentation and reduplication. In 98.9% of GCA biopsy positive cases, inflammatory infiltrate were present, with transmural (41.6%) and adventitia (18.0%) recorded as the predominant sites of inflammation. Giant cells were seen in 67 (75.3%) of GCA biopsy positive cases. Completely occluded vessels were found in 20 cases, usually due to internal hyperplasia (in 16), although 4 cases had additional thrombus. Furthermore, 7 cases had evidence of recanalisation in at least one section of the biopsy. We analysed the clinician’s initial assessment at baseline (prior to biopsy): 88, 189 and 73 out of 350 cases were defined as possible, probable or definite GCA: of these, 7 (8.0%), 45 (23.8%) and 37 (50.7%) respectively had a biopsy consistent with GCA.
Histological features in biopsy positive patients with GCA are not confined to one particular form of inflammation. The most common finding was transmural inflammation. We report a relatively low number of positive biopsies (89/350) which may reflect the low index of suspicion of GCA in this group, technical difficulties in obtaining an adequate sample, or skip lesions missed due to inadequate length of tissue, or the effects of glucocorticoid therapy in changing the biopsy result. Our findings highlight the need for a better diagnostic strategy for patients with suspected temporal arteritis.
A. P. Diamantopoulos,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/preliminary-analysis-of-histological-findings-in-diagnosis-of-giant-cell-arteritis-biopsy-positive-patients/