{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T12:12:15Z","timestamp":1783944735695,"version":"3.55.0"},"reference-count":15,"publisher":"BMJ","issue":"7","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2026,6,26]]},"published-print":{"date-parts":[[2026,7]]},"abstract":"<jats:p>Crossed fused renal ectopia is a rare, typically asymptomatic congenital malformation of the upper urinary tract. Diagnosis is often incidental during imaging. We present the case of a man in his 50s presenting to the Emergency Department with his first episode of acute abdominal pain, secondary to nephrolithiasis. CT imaging suspected a crossed fused right-to-left renal ectopia, with the unusual finding of a single ureter crossing the midline and inserting into the bladder on the contralateral side. This anatomical variant should significantly influence clinical management and follow-up. We describe the diagnostic process, implications and embryological considerations of this rare condition. We highlight the importance of contrast-enhanced CT in evaluating suspected or confirmed urinary tract malformations.<\/jats:p>","DOI":"10.1136\/bcr-2025-266636","type":"journal-article","created":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T11:35:14Z","timestamp":1783942514000},"page":"e266636","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Crossed fused right-to-left renal ectopia with single ureter"],"prefix":"10.1136","volume":"19","author":[{"given":"Simon","family":"Chilou","sequence":"first","affiliation":[{"name":"Urology, Groupement Hospitalier de l\u2019Ouest l\u00e9manique, Nyon, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Camille","family":"Chilou Nicolle","sequence":"additional","affiliation":[{"name":"Urology, Groupement Hospitalier de l\u2019Ouest l\u00e9manique, Nyon, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Karim","family":"Kellou","sequence":"additional","affiliation":[{"name":"Urology, Groupement Hospitalier de l\u2019Ouest l\u00e9manique, Nyon, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andreia","family":"Reis","sequence":"additional","affiliation":[{"name":"Urology, Groupement Hospitalier de l\u2019Ouest l\u00e9manique, Nyon, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"239","published-online":{"date-parts":[[2026,7,13]]},"reference":[{"key":"2026071304350562000_19.7.e266636.1","unstructured":"Shapiro E , Telegrafi S . Anomalies of form and fusion, crossed renal ectopia with and without fusion. In: Wein AJ , ed. Campbell-walsh urology. Philadelphia: WB Saunders, 2016: 2988\u201393."},{"key":"2026071304350562000_19.7.e266636.2","doi-asserted-by":"publisher","DOI":"10.1159\/000277442"},{"key":"2026071304350562000_19.7.e266636.3","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1016\/j.jpurol.2019.06.019","article-title":"Crossed fused renal ectopia in children: a review of clinical profile, surgical challenges, and outcome","volume":"15","author":"Loganathan","year":"2019","journal-title":"J Pediatr Urol"},{"key":"2026071304350562000_19.7.e266636.4","doi-asserted-by":"publisher","DOI":"10.1007\/s00404-001-0265-4"},{"key":"2026071304350562000_19.7.e266636.5","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9610(57)90680-3"},{"key":"2026071304350562000_19.7.e266636.6","doi-asserted-by":"crossref","DOI":"10.1136\/bcr-2015-213050","article-title":"Crossed fused renal ectopia with chyluria: a rare presentation","volume":"2016","author":"Singh","year":"2016","journal-title":"BMJ Case Rep"},{"key":"2026071304350562000_19.7.e266636.7","article-title":"Crossed fused renal ectopia (pancake type) with single ureter: A case report","volume":"39","author":"Habtemichael","year":"2021","journal-title":"Urol Case Rep"},{"key":"2026071304350562000_19.7.e266636.8","doi-asserted-by":"crossref","first-page":"321","DOI":"10.1590\/S1677-55382004000400011","article-title":"Cake kidney drained by single ureter","volume":"30","author":"Calado","year":"2004","journal-title":"Int braz j urol"},{"key":"2026071304350562000_19.7.e266636.9","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1007\/s40746-019-00166-3","article-title":"Congenital Anomalies of the Kidney and Urinary Tract: A Clinical Review","volume":"5","author":"Stonebrook","year":"2019","journal-title":"Curr Treat Options Pediatr"},{"key":"2026071304350562000_19.7.e266636.10","unstructured":"Jung H, A , Neisius A , et al . Urolithiasis. In: European Association of Urology Guidelines. Presented at EAU Annual Congress. 2025."},{"key":"2026071304350562000_19.7.e266636.11","doi-asserted-by":"publisher","DOI":"10.4103\/0971-9261.107006"},{"key":"2026071304350562000_19.7.e266636.12","first-page":"91","article-title":"Practical approach to metabolic evaluation and treatment of the recurrent stone patient","volume":"107","author":"Bandi","year":"2008","journal-title":"WMJ"},{"key":"2026071304350562000_19.7.e266636.13","first-page":"D11","article-title":"Crossed fused ectopic kidney: A case report","volume":"11","author":"Maheshwari","year":"2017","journal-title":"J Clin Diagn Res"},{"key":"2026071304350562000_19.7.e266636.14","doi-asserted-by":"crossref","first-page":"125","DOI":"10.1097\/MOU.0000000000000855","article-title":"Guideline of the guidelines: urolithiasis","volume":"31","author":"Quhal","year":"2021","journal-title":"Curr Opin Urol"},{"key":"2026071304350562000_19.7.e266636.15","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(98)01295-1"}],"container-title":["BMJ Case Reports"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1136\/bcr-2025-266636","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,13]],"date-time":"2026-07-13T11:35:16Z","timestamp":1783942516000},"score":1,"resource":{"primary":{"URL":"https:\/\/casereports.bmj.com\/lookup\/doi\/10.1136\/bcr-2025-266636"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7]]},"references-count":15,"journal-issue":{"issue":"7","published-online":{"date-parts":[[2026,7,13]]},"published-print":{"date-parts":[[2026,7]]}},"alternative-id":["10.1136\/bcr-2025-266636"],"URL":"https:\/\/doi.org\/10.1136\/bcr-2025-266636","relation":{},"ISSN":["1757-790X"],"issn-type":[{"value":"1757-790X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7]]}}}