{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T14:02:41Z","timestamp":1782741761164,"version":"3.54.5"},"reference-count":11,"publisher":"BMJ","issue":"2","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,1,27]]},"published-print":{"date-parts":[[2026,2]]},"abstract":"<jats:p>\n                    Isolated muscle vasculitis (IMV) is an uncommon vasculitic entity restricted to skeletal muscle and may present without weakness or creatine kinase elevation, making diagnosis difficult. A woman in her 60s presented with a 3-week history of migratory myalgia involving the thighs, shoulders and flanks. Laboratory tests showed leukocytosis, normocytic anaemia, thrombocytosis, markedly elevated inflammatory markers, normal creatine kinase and mildly increased aldolase. MRI of the thighs demonstrated patchy muscle oedema, while extensive infectious and autoimmune evaluation was unrevealing. Muscle biopsy revealed perimysial lymphohistiocytic vasculitis composed of CD4\n                    <jats:sup>+<\/jats:sup>\n                    T cells and histiocytes without myofibre necrosis, confirming IMV. She improved rapidly with oral prednisone, and methotrexate was initiated as a steroid-sparing agent. This case highlights the importance of considering IMV in patients with unexplained myalgia and systemic inflammation despite normal muscle enzymes and underscores the essential role of MRI and muscle biopsy in diagnosis. Early immunosuppressive therapy leads to favourable outcomes.\n                  <\/jats:p>","DOI":"10.1136\/bcr-2025-271218","type":"journal-article","created":{"date-parts":[[2026,2,10]],"date-time":"2026-02-10T15:22:32Z","timestamp":1770736952000},"page":"e271218","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":1,"title":["Isolated muscle vasculitis as a mimic of inflammatory myopathy"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-4383-0639","authenticated-orcid":false,"given":"Ko","family":"Takamatsu","sequence":"first","affiliation":[{"name":"Medicine, University of Hawai\u2019i at Manoa John A Burns School of Medicine, Honolulu, Hawaii, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Devy","family":"Setyono","sequence":"additional","affiliation":[{"name":"Rheumatology, Straub Medical Center, Honolulu, Hawaii, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,2,10]]},"reference":[{"key":"2026021023551757000_19.2.e271218.1","doi-asserted-by":"crossref","DOI":"10.1002\/acr2.70062","article-title":"Muscle Vasculitis: A Novel Delineation of Distinct Subsets of Disease","volume":"7","author":"Khoo","year":"2025","journal-title":"ACR Open Rheumatol"},{"key":"2026021023551757000_19.2.e271218.2","doi-asserted-by":"crossref","first-page":"776","DOI":"10.1016\/S1474-4422(25)00233-9","article-title":"Advances in the classification and management of idiopathic inflammatory myopathies","volume":"24","author":"Raaphorst","year":"2025","journal-title":"Lancet Neurol"},{"key":"2026021023551757000_19.2.e271218.3","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMra011913"},{"key":"2026021023551757000_19.2.e271218.4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/art.37715","article-title":"Revised International Chapel Hill consensus conference nomenclature of vasculitides","volume":"65","author":"Jennette","year":"2012","journal-title":"Arthritis Rheum"},{"key":"2026021023551757000_19.2.e271218.5","doi-asserted-by":"crossref","first-page":"503","DOI":"10.1016\/j.semarthrit.2019.12.002","article-title":"Polyarteritis nodosa isolated to muscles: a case series with a review of the literature","volume":"50","author":"Ganeshanandan","year":"2020","journal-title":"Semin Arthritis Rheum"},{"key":"2026021023551757000_19.2.e271218.6","doi-asserted-by":"publisher","DOI":"10.1097\/BOR.0b013e3282f176a0"},{"key":"2026021023551757000_19.2.e271218.7","doi-asserted-by":"crossref","first-page":"103602","DOI":"10.1016\/j.autrev.2024.103602","article-title":"Early skeletal muscle manifestations in polyarteritis nodosa and ANCA-associated vasculitis","volume":"23","author":"Shimojima","year":"2024","journal-title":"Autoimmun Rev"},{"key":"2026021023551757000_19.2.e271218.8","doi-asserted-by":"publisher","DOI":"10.1093\/qjmed\/hch055"},{"key":"2026021023551757000_19.2.e271218.9","first-page":"871","article-title":"Unusual Presentation of Polyarteritis Nodosa","volume":"28","author":"Hall","year":"2001","journal-title":"J Rheumatol"},{"key":"2026021023551757000_19.2.e271218.10","doi-asserted-by":"publisher","DOI":"10.1007\/s10067-002-0688-8"},{"key":"2026021023551757000_19.2.e271218.11","doi-asserted-by":"crossref","first-page":"2115","DOI":"10.1007\/s00296-017-3841-z","article-title":"Muscular vasculitis confined to lower limbs: description of two case reports and a review of the literature","volume":"37","author":"Tripoli","year":"2017","journal-title":"Rheumatol Int"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-271218","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,2,11]],"date-time":"2026-02-11T07:55:28Z","timestamp":1770796528000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-271218"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,2]]},"references-count":11,"journal-issue":{"issue":"2","published-online":{"date-parts":[[2026,2,10]]},"published-print":{"date-parts":[[2026,2]]}},"alternative-id":["10.1136\/bcr-2025-271218"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-271218","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,2]]}}}