{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,11]],"date-time":"2026-08-11T11:27:41Z","timestamp":1786447661888,"version":"build-2736575974"},"reference-count":24,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,11]],"date-time":"2026-08-11T00:00:00Z","timestamp":1786406400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Oncol."],"abstract":"<jats:p>Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm for which definitive radiotherapy in the retroperitoneum remains largely undefined, particularly when dose escalation must be balanced against the preservation of adjacent critical organs. A 59-year-old woman presented with a 10-day history of fever and abdominopelvic pain. Physical examination revealed deep tenderness in the right lower quadrant, and laboratory testing demonstrated leukocytosis. Imaging identified a 9.2\u00a0cm retroperitoneal mass invading the right ureter and inferior vena cava. Biopsy confirmed IMT, and capture-based next-generation sequencing revealed no class I actionable alterations. Given the unfavorable surgical anatomy and limited response to corticosteroids, curative-intent resection was precluded. The patient was treated with definitive dose-escalated volumetric modulated arc therapy (VMAT) employing a simultaneous integrated boost strategy (66 Gy\/33 fractions to the boost volume and 50 Gy to the conventional planning target volume), with spatial sparing of adjacent organs at risk. Complete radiographic response was achieved at one month, without grade \u22652 treatment-related adverse events. At 19-month follow-up, the patient remained disease-free with stable renal function. This case demonstrates that dose-escalated VMAT with spatial organ avoidance can achieve durable complete remission in unresectable retroperitoneal IMT while preserving organ function, supporting its consideration as a curative-intent strategy in this challenging clinical setting.<\/jats:p>","DOI":"10.3389\/fonc.2026.1818998","type":"journal-article","created":{"date-parts":[[2026,8,11]],"date-time":"2026-08-11T10:28:21Z","timestamp":1786444101000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Case Report: Dose-escalated volumetric modulated arc therapy achieving bowel and renal protection for large retroperitoneal inflammatory myofibroblastic tumor invading ureter and inferior vena cava"],"prefix":"10.3389","volume":"16","author":[{"given":"Jiarui","family":"Zhang","sequence":"first","affiliation":[{"name":"Department of Radiation Oncology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tianhao","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cuihua","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Pathology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siming","family":"Shi","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Peng","family":"Zhen","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fang","family":"Fang","sequence":"additional","affiliation":[{"name":"Department of Radiation Oncology, Chifeng Tumor Hospital","place":["Chifeng, Inner Mongolia Autonomous Region, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,11]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1097\/00000478-199508000-00001","article-title":"Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor): a clinicopathologic and immunohistochemical study of 84 cases","volume":"19","author":"Coffin","year":"1995","journal-title":"Am J Surg Pathol"},{"key":"B2","volume-title":"WHO Classification of Tumours of Soft Tissue and Bone","year":"2020"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1016\/j.rcl.2015.12.005","article-title":"Inflammatory myofibroblastic tumors","volume":"54","author":"Surabhi","year":"2016","journal-title":"Radiologic Clinics North America"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.32604\/or.2024.050350","article-title":"Inflammatory myofibroblastic tumor: from molecular diagnostics to current treatment","volume":"32","author":"Chmiel","year":"2024","journal-title":"Oncol Res"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1136\/jcp.2007.049387","article-title":"Inflammatory myofibroblastic tumours: where are we now","volume":"61","author":"Gleason","year":"2008","journal-title":"J Clin Pathol"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1038\/modpathol.2017.69","article-title":"Inflammatory myofibroblastic tumor of the uterus: a clinicopathological, immunohistochemical, and molecular analysis of 13 cases highlighting their broad morphologic spectrum","volume":"30","author":"Bennett","year":"2017","journal-title":"Mod Pathol"},{"key":"B7","doi-asserted-by":"publisher","DOI":"10.1111\/1759-7714.14914","article-title":"Surgical treatment for lung metastasis of inflammatory myofibroblastic tumor of the lung: a case report","volume":"14","author":"Iwai","year":"2023","journal-title":"Thorac Cancer"},{"key":"B8","doi-asserted-by":"publisher","DOI":"10.1177\/1078155219879757","article-title":"How long should we continue crizotinib in ALK translocation-positive inflammatory myofibroblastic tumors? 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