{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T15:21:27Z","timestamp":1761664887375,"version":"build-2065373602"},"reference-count":20,"publisher":"Wiley","license":[{"start":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T00:00:00Z","timestamp":1761609600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["J of Clinical Ultrasound"],"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:p>\n                    Retroperitoneal extra\u2010adrenal paragangliomas are rare neuroendocrine tumors that frequently arise in a confined anatomical space bordered by the right side of the abdominal aorta, the left side of the inferior vena cava, and the posterior aspect of the horizontal part of the duodenum (hereafter referred to as the duodenum\u2010adjacent aortocaval region). Although ultrasonography (US) is a noninvasive and useful modality for initial diagnosis, detailed imaging characteristics of such tumors have not been sufficiently reported. This report aimed to describe the anatomical location and ultrasonographic features of three cases of retroperitoneal extra\u2010adrenal paraganglioma, with a focus on blood flow evaluation using superb microvascular imaging (SMI) and contrast\u2010enhanced ultrasound (CEUS). We retrospectively analyzed B\u2010mode US, SMI, CEUS, computed tomography (CT), magnetic resonance imaging (MRI), and\n                    <jats:sup>123<\/jats:sup>\n                    I\u2010MIBG scintigraphy findings in all three cases. In every case, tumors were located in the duodenum\u2010adjacent aortocaval region. US revealed well\u2010defined, hypoechoic, oval\u2010shaped masses with heterogeneous internal structures. SMI showed abundant intratumoral blood flow, while CEUS demonstrated contrast enhancement. SMI under contrast enhancement revealed blood flow that was not visible with conventional SMI. Our findings indicate that retroperitoneal extra\u2010adrenal paragangliomas exhibit characteristic morphology and vascularity on US. The combined use of SMI and CEUS may further enhance diagnostic accuracy and contribute to US as an important noninvasive diagnostic tool. Moreover, when a mass is identified in the duodenum\u2010adjacent aortocaval region, paraganglioma should be considered in the differential diagnosis.\n                  <\/jats:p>","DOI":"10.1002\/jcu.70112","type":"journal-article","created":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T15:17:39Z","timestamp":1761664659000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Anatomical Location and Ultrasonographic Features of Retroperitoneal Extra\u2010Adrenal Paragangliomas: A Report of Three Cases"],"prefix":"10.1002","author":[{"ORCID":"https:\/\/orcid.org\/0009-0006-5486-2441","authenticated-orcid":false,"given":"Shingo","family":"Shioya","sequence":"first","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuki","family":"Okubo","sequence":"additional","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Naomi","family":"Hayashi","sequence":"additional","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Takashi","family":"Sasaki","sequence":"additional","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yuuki","family":"Sakaguchi","sequence":"additional","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Katsuya","family":"Nakamura","sequence":"additional","affiliation":[{"name":"Department of Ultrasound Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hiroshi","family":"Sugita","sequence":"additional","affiliation":[{"name":"Department of General Internal Medicine Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Tomomi","family":"Hayashi","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Surgery Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jun","family":"Kadono","sequence":"additional","affiliation":[{"name":"Department of Gastrointestinal Surgery Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Koichiro","family":"Shigeta","sequence":"additional","affiliation":[{"name":"Department of Gastroenterology Kirishima Medical Center  Kirishima Japan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2025,10,28]]},"reference":[{"issue":"2","key":"e_1_2_8_2_1","first-page":"987","article-title":"Superb Microvascular Imaging and CEUS in Abdominal Mass Evaluation: A Comparative Study With CT and MRI","volume":"35","author":"Aslan S.","year":"2025","journal-title":"European Radiology"},{"key":"e_1_2_8_3_1","doi-asserted-by":"crossref","first-page":"699","DOI":"10.1016\/j.ecl.2006.09.014","article-title":"Emergencies Caused by Pheochromocytoma, Neuroblastoma, or Paraganglioma","volume":"35","author":"Brouwers F. 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D.","year":"2003","journal-title":"Radiographics"},{"issue":"6","key":"e_1_2_8_15_1","first-page":"1885","article-title":"Clinical Utility of CEUS Combined With SMI for Assessing Intratumoral Vascularity in Abdominal Tumors","volume":"49","author":"Li X.","year":"2024","journal-title":"Abdominal Radiology"},{"key":"e_1_2_8_16_1","first-page":"65","article-title":"Imaging\u2010Pathologic Correlation of Gastrointestinal Stromal Tumors (in Japanese)","volume":"21","author":"Maruyama Y.","year":"2019","journal-title":"Japanese Journal of Gastrointestinal Imaging"},{"key":"e_1_2_8_17_1","first-page":"329","article-title":"Clinical Utility of Superb Microvascular Imaging in Abdominal Ultrasonography (in Japanese)","volume":"45","author":"Mukai H.,","year":"2018","journal-title":"Journal of Medical Ultrasonics"},{"key":"e_1_2_8_18_1","first-page":"240","article-title":"Diagnostic Value of CEUS in the Evaluation of Hypervascular Abdominal Tumors","volume":"36","author":"Spiesecke P.","year":"2015","journal-title":"Ultraschall in der Medizin"},{"issue":"3","key":"e_1_2_8_19_1","first-page":"421","article-title":"Contrast\u2010Enhanced Ultrasound in Abdominal Tumor Characterization: Recent Updates and Future Perspectives","volume":"50","author":"Urraro F.","year":"2024","journal-title":"Ultrasound in Medicine & Biology"},{"key":"e_1_2_8_20_1","first-page":"25","article-title":"Sonographic Findings of Abdominal Schwannoma (in Japanese)","volume":"48","author":"Wang J.","year":"2021","journal-title":"Journal of Medical Ultrasonics"},{"key":"e_1_2_8_21_1","first-page":"682","article-title":"Extra\u2010Adrenal Paragangliomas: Diagnosis and Management","volume":"215","author":"Whalen R. K.","year":"1992","journal-title":"Annals of Surgery"}],"container-title":["Journal of Clinical Ultrasound"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/jcu.70112","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,28]],"date-time":"2025-10-28T15:17:43Z","timestamp":1761664663000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/jcu.70112"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,10,28]]},"references-count":20,"alternative-id":["10.1002\/jcu.70112"],"URL":"https:\/\/doi.org\/10.1002\/jcu.70112","archive":["Portico"],"relation":{},"ISSN":["0091-2751","1097-0096"],"issn-type":[{"value":"0091-2751","type":"print"},{"value":"1097-0096","type":"electronic"}],"subject":[],"published":{"date-parts":[[2025,10,28]]},"assertion":[{"value":"2025-05-26","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-10-05","order":2,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2025-10-28","order":3,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}],"article-number":"jcu.70112"}}