Temporal artery biopsy - A diagnostic tool for systemic necrotizing vasculitis

Objective. To describe the clinical, biologic, and histologic features of t emporal artery biopsy (TAB)localized systemic necrotizing vasculitides (SNV ), and to assess their frequency among elderly patients undergoing TAB for suspected giant cell (temporal) arteritis (GCA), Methods, The frequency of a TAB localization of SNV was prospectively asses sed in a multicenter study of elderly patients undergoing TAB for suspected GCA, All patients with SNV fulfilling the American College of Rheumatology criteria for a specific vasculitic syndrome and with evidence of vasculiti s on TAB were included in a retrospective, descriptive study. Results, SNV was diagnosed based on the TAB in 1.4% of the patients with su spected GCA and in 4.5% of the positive (inflamed) TAB specimens. We retros pectively selected 27 patients (18 female, 9 male; mean +/- SD age 62 +/- 1 5 years, range 22-79 years) with SNV and TAB-localized vasculitis, Only 2 o f these patients were known to have SNV before TAB localization, Twenty-two patients (81%) had cephalic symptoms, including jaw claudication in 33%, c linically abnormal temporal arteries in 33%, and neuro-ophthalmologic sympt oms in 11%, All patients had systemic symptoms suggestive of SNV and histol ogically proven NV in the TAB specimens (70%) or elsewhere in other biopsy sites (74%), Abnormal biologic results suggestive of SNV were present in 17 patients (63%), For 4 patients, the TAB-documented involvement led to init ial misdiagnoses of GCA, and systemic manifestations that developed under s teroid therapy revealed the correct diagnosis. The final diagnoses of the p atients were polyarteritis nodosa (PAN) (n =11), Churg-Strauss syndrome (n = 6), micropolyangiitis (n = 3), Wegener's granulomatosis (n = 3), hepatiti s B virus-related PAN (n = 2), hepatitis C virus-related cryoglobulinemic v asculitis (n = 1), and rheumatoid vasculitis (n = 1), Conclusion. TAB-localized SNV presents a major diagnostic dilemma because i t can mimic GCA. Careful analysis of clinical, biologic, and histologic dat a should lead to the correct diagnosis and help guide the clinician's choic e of appropriate therapy.