THE INFLUENCE OF SECTIONAL INTERVAL ON THE RELIABILITY OF TEMPORAL ARTERIAL BIOPSIES IN POLYMYALGIA-RHEUMATICA

Temporal arterial biopsies from 27 patients with a clinical diagnosis of pure polymyalgia rheumatica (PMR) were examined using light microsc opy on paraffin and plastic sections. The primary routine examination of the paraffin-embedded parts of the biopsies (biopsy length: 12.7+/- 4.5 mm, sub-segments: 4.9+/-1.2 mm) revealed 4 positive cases, whereas the primary examination of the smaller plastic-embedded parts showed inflammation in 6 cases (biopsy length: 2.7+/-1.2 mm, sub-segments: 0. 7+/-0.3 mm), Serial sectioning with a 50 mu m interval of arteries whi ch were negative primarily revealed three new positive cases in the pa raffin-embedded material (total length: 174.0 mm), whereas sectioning the plastic-embedded material (total length: 52.8 mm) produced one mor e positive artery. All the new cases displayed a focal inflammatory pr ocess in atrophic, calcified arterial segments. The high yield of posi tive biopsies in the present material (11 of 27; 40.7%) demonstrates t he diagnostic value of temporal arterial biopsy in PMR and the importa nce of a careful histologic examination. The results also indicate the influence of biopsy length on the yield of positive biopsies. The div ision of fixed temporal arterial biopsies into approximately 1-mm-long sub-segments before the embedding and the further serial sectioning o f those negative biopsies which are atrophic and/or calcified is recom mended in cases of pure PMR.