(A) Hypoechoic ‘halo sign’ of ... (A) Hypoechoic ‘halo sign’ of the left temporal artery. (B) Haematoxylin and eosin, magnification 10×. (C) Arterial wall with deposits of an amorphous eosinophilic material. Orcein, magnification 10×. (D) Segment of collapsed arterial wall. Immunohistochemical kappa, magnification 10×. (E) Kappa chain deposits. Congo Red, magnification 10×; green birefringence with polarized light. Unless provided in the caption above, the following copyright applies to the content of this slide: © The Author(s) 2019. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For permissions, please email: journals.permissions@oup.comThis article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Rheumatology (Oxford), kez182, https://doi.org/10.1093/rheumatology/kez182 The content of this slide may be subject to copyright: please see the slide notes for details.