{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T05:47:11Z","timestamp":1785822431117,"version":"3.56.0"},"reference-count":11,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T00:00:00Z","timestamp":1785801600000},"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. Surg."],"abstract":"<jats:p>Intraoperative frozen-section (FS) margin assessment is essential for guiding precise resection in perihilar cholangiocarcinoma (pCCA). However, freezing artifacts, superficial sampling, drainage-related reactive epithelial changes, and subtle cytologic atypia in well-differentiated adenocarcinoma can make intraoperative interpretation difficult. We report a 70-year-old woman with Bismuth-Corlette type II pCCA who underwent radical extrahepatic bile duct resection after PTBD-mediated biliary decompression. Intraoperative FS of the distal bile duct margin showed atypical glands of undetermined nature, while proximal margins were negative. Because additional caudal resection would probably have required combined pancreaticoduodenectomy in an elderly patient recovering from severe obstructive jaundice, the surgical team avoided extended resection after real-time surgical-pathological discussion. Permanent sections and immunohistochemistry subsequently confirmed well-differentiated adenocarcinoma involving the distal margin, perineural invasion, and regional lymph-node metastasis, consistent with an unintended R1 resection. This case illustrates that an indeterminate FS margin should be regarded as a high-risk gray-zone finding rather than a safe negative result. We propose a three-tier margin risk-stratification framework in which a \u201cpresumed positive\u201d principle triggers repeat oriented sampling, intraoperative multidisciplinary consultation, and individualized balancing of oncologic radicality against physiological reserve. When aggressive resection is contraindicated, meticulous documentation, early adjuvant therapy, and rigorous long-term surveillance are essential.<\/jats:p>","DOI":"10.3389\/fsurg.2026.1899125","type":"journal-article","created":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T05:36:10Z","timestamp":1785821770000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Intraoperative indeterminate frozen-section margin leading to an unintended R1 resection in perihilar cholangiocarcinoma: a case report and decision-making framework"],"prefix":"10.3389","volume":"13","author":[{"given":"Xiaojing","family":"Li","sequence":"first","affiliation":[{"name":"Department of Pathology, The Affiliated Hospital of Inner Mongolia Medical University","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jia","family":"Wang","sequence":"additional","affiliation":[{"name":"Inner Mongolia Autonomous Region People's Hospital","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Liye","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Hepatobiliary Surgery, The Affiliated Hospital of Inner Mongolia Medical University","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ying","family":"Wei","sequence":"additional","affiliation":[{"name":"Central Laboratory, The Affiliated Hospital of Inner Mongolia Medical University","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanan","family":"Wang","sequence":"additional","affiliation":[{"name":"Department of Pathology, The Affiliated Hospital of Inner Mongolia Medical University","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jiaxin","family":"Sun","sequence":"additional","affiliation":[{"name":"Central Laboratory, The Affiliated Hospital of Inner Mongolia Medical University","place":["Inner Mongolia, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,4]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"2942","DOI":"10.3390\/curroncol30030225","article-title":"Current perspectives in liver transplantation for perihilar cholangiocarcinoma","volume":"30","author":"Giovinazzo","year":"2023","journal-title":"Current Oncology"},{"key":"B2","doi-asserted-by":"publisher","first-page":"48","DOI":"10.1186\/s12957-024-03329-1","article-title":"Preoperative predictors for non-resectability in perihilar cholangiocarcinoma","volume":"22","author":"Otto","year":"2024","journal-title":"World J Surg Oncol"},{"key":"B3","doi-asserted-by":"publisher","first-page":"10157","DOI":"10.2147\/CMAR.S230620","article-title":"Preoperative bilirubin level predicts overall survival and tumor recurrence after resection for perihilar cholangiocarcinoma patients","volume":"11","author":"Li","year":"2019","journal-title":"Cancer Manag Res"},{"key":"B4","doi-asserted-by":"publisher","first-page":"zrag010","DOI":"10.1093\/bjsopen\/zrag010","article-title":"Clinical implications of an intraoperative margin-positive distal bile duct in perihilar cholangiocarcinoma: international multicentre cohort study","volume":"10","author":"Al-Saffar","year":"2026","journal-title":"BJS open"},{"key":"B5","doi-asserted-by":"publisher","first-page":"18","DOI":"10.1159\/000514032","article-title":"Surgical therapy for perihilar cholangiocarcinoma: state of the art","volume":"37","author":"Nooijen","year":"2021","journal-title":"Visceral Medicine"},{"key":"B6","doi-asserted-by":"publisher","first-page":"2104","DOI":"10.1245\/s10434-008-0003-2","article-title":"Clinical significance of intraoperative bile duct margin assessment for hilar cholangiocarcinoma","volume":"15","author":"Endo","year":"2008","journal-title":"Ann Surg Oncol"},{"key":"B7","doi-asserted-by":"publisher","first-page":"111051","DOI":"10.1016\/j.ijscr.2025.111051","article-title":"Klatskin tumor - A case report of hilar cholangiocarcinoma with hepatic metastasis","volume":"128","author":"Mirzaei","year":"2025","journal-title":"Int J Surg Case Rep"},{"key":"B8","doi-asserted-by":"publisher","first-page":"233","DOI":"10.3390\/diagnostics13020233","article-title":"Diagnosis of cholangiocarcinoma","volume":"13","author":"Shin","year":"2023","journal-title":"Diagnostics (Basel, Switzerland)"},{"key":"B9","doi-asserted-by":"publisher","first-page":"100737","DOI":"10.1016\/j.aohep.2022.100737","article-title":"Clinical treatment of cholangiocarcinoma: an updated comprehensive review","volume":"27","author":"Elvevi","year":"2022","journal-title":"Ann Hepatol"},{"key":"B10","doi-asserted-by":"publisher","first-page":"219","DOI":"10.1159\/000538687","article-title":"Challenges and pitfalls in pancreatobiliary cytopathology","volume":"68","author":"Scarpa-Carniello","year":"2024","journal-title":"Acta Cytol"},{"key":"B11","doi-asserted-by":"publisher","first-page":"442","DOI":"10.4103\/njcp.njcp_23_26","article-title":"Clinical outcomes and prognostic factors of percutaneous transhepatic biliary drainage in malignant biliary obstruction: a retrospective study of 383 patients","volume":"29","author":"Uzunkaya","year":"2026","journal-title":"Niger J Clin Pract"}],"container-title":["Frontiers in Surgery"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fsurg.2026.1899125\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T05:36:11Z","timestamp":1785821771000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fsurg.2026.1899125\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,4]]},"references-count":11,"alternative-id":["10.3389\/fsurg.2026.1899125"],"URL":"https:\/\/doi.org\/10.3389\/fsurg.2026.1899125","relation":{},"ISSN":["2296-875X"],"issn-type":[{"value":"2296-875X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,4]]},"article-number":"1899125"}}