{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T09:52:23Z","timestamp":1791366743950,"version":"4.3.1"},"reference-count":23,"publisher":"Georg Thieme Verlag KG","issue":"04","license":[{"start":{"date-parts":[[2026,10,6]],"date-time":"2026-10-06T00:00:00Z","timestamp":1791244800000},"content-version":"vor","delay-in-days":5,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurol Surg Rep"],"published-print":{"date-parts":[[2026,10]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Background Skull base chondrosarcomas are rare and locally aggressive tumors with heterogeneous biology accounting for 0.1\u20130.2% of all intracranial tumors. Dedifferentiated chondrosarcoma is an exceptionally uncommon and aggressive variant, seldom seen at the skull base. We report a recurrent clival chondrosarcoma with a small, dedifferentiated component, and an unusually long latency after initial treatment.<\/jats:p>\n                  <jats:p>Case Report A 66-year-old woman was referred with a recurrent progressive clival lesion, initially suspected to be a chordoma. She had undergone subtotal resection followed by single-fraction radiosurgery (25 Gy) 32 years earlier. Surveillance imaging demonstrated interval growth compared with imaging 5 years earlier, prompting repeat subtotal resection. Histopathology revealed a conventional chondrosarcoma with a dedifferentiated component comprising &lt;5% of tumor area and an isocitrate dehydrogenase 1 (IDH1) R132 mutation. The patient declined adjuvant radiotherapy. Three years later, she developed worsening diplopia, new right oculomotor palsy, and headache with radiologic progression, prompting repeat subtotal resection. She currently awaits postoperative proton beam radiotherapy.<\/jats:p>\n                  <jats:p>Conclusion This case highlights a key diagnostic challenge of distinguishing chondrosarcoma from chordoma, and underscores the importance of meticulous histologic sampling to detect small dedifferentiated foci that may otherwise result in undergrading and undertreatment. The heterogeneity in clinical behavior observed across histopathological subtypes further underscores the necessity for grade\/subtype-driven treatment regimens. Therefore, accurate subtype classification and molecular annotation may better inform treatment strategy and follow-up. Lastly, the rarity of dedifferentiated skull base chondrosarcoma reinforces the need for multicenter registries to further understand the behavior and vulnerabilities of this rare disease.<\/jats:p>","DOI":"10.1055\/a-2964-8969","type":"journal-article","created":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T08:37:37Z","timestamp":1791362257000},"page":"e177-e182","source":"Crossref","is-referenced-by-count":0,"title":["Recurrent Dedifferentiated Clival Chondrosarcoma Presenting 32 Years after Initial Treatment: A Case Report"],"prefix":"10.1055","volume":"87","author":[{"ORCID":"https:\/\/orcid.org\/0009-0007-2911-1854","authenticated-orcid":false,"given":"Pawan Kishore","family":"Ravindran","sequence":"additional","affiliation":[{"name":"Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"],"department":["Department of Neurosurgery"]},{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Mental Health and Neuroscience Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Limburg, The Netherlands","place":["Maastricht"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8263-9550","authenticated-orcid":false,"given":"Max E.","family":"Keizer","sequence":"additional","affiliation":[{"name":"Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"],"department":["Department of Neurosurgery"]},{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Mental Health and Neuroscience Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Limburg, The Netherlands","place":["Maastricht"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zeynep B.","family":"Erdem","sequence":"additional","affiliation":[{"name":"Leiden University Medical Center, The Netherlands","place":["Leiden"],"department":["Department of Pathology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henricus P.M.","family":"Kunst","sequence":"additional","affiliation":[{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Radboud Institute of Health Sciences, Radboud University Medical Center, Gelderland, The Netherlands","place":["Nijmegen"],"department":["Department of Ear, Nose and Throat"]},{"name":"Maastricht University Medical Center+, LI, The Netherlands","place":["Maastricht"],"department":["Department of Otolaryngology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koos E.","family":"Hovinga","sequence":"additional","affiliation":[{"name":"Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"],"department":["Department of Neurosurgery"]},{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Mental Health and Neuroscience Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Limburg, The Netherlands","place":["Maastricht"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jasper","family":"van Aalst","sequence":"additional","affiliation":[{"name":"Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"],"department":["Department of Neurosurgery"]},{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Mental Health and Neuroscience Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Limburg, The Netherlands","place":["Maastricht"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasin","family":"Temel","sequence":"additional","affiliation":[{"name":"Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"],"department":["Department of Neurosurgery"]},{"name":"Dutch Academic Alliance Skull Base Pathology, Maastricht University Medical Center+, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Mental Health and Neuroscience Research Institute, Faculty of Health, Medicine and Life Sciences, Maastricht University, Limburg, The Netherlands","place":["Maastricht"]},{"name":"Faculty of Medicine, Istanbul Atlas Universitesi, \u0130stanbul, T\u00fcrkiye","place":["Istanbul"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"194","published-online":{"date-parts":[[2026,10,6]]},"reference":[{"issue":"07","key":"ref1","doi-asserted-by":"crossref","first-page":"2506","DOI":"10.3390\/jcm12072506","article-title":"Chondrosarcoma: a clinical review","volume":"12","author":"A Gazendam","year":"2023","journal-title":"J Clin Med"},{"issue":"07","key":"ref2","doi-asserted-by":"crossref","first-page":"637","DOI":"10.2217\/fon-2016-0226","article-title":"Novel therapeutic approaches in chondrosarcoma","volume":"13","author":"G Polychronidou","year":"2017","journal-title":"Future Oncol"},{"key":"ref3","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jocn.2015.10.029","article-title":"Skull base chondrosarcoma","volume":"24","author":"M Awad","year":"2016","journal-title":"J Clin Neurosci"},{"issue":"05","key":"ref4","doi-asserted-by":"crossref","first-page":"856","DOI":"10.3390\/cancers16050856","article-title":"Skull-base chondrosarcoma: a systematic review of the role of postoperative radiotherapy","volume":"16","author":"P K Ravindran","year":"2024","journal-title":"Cancers"},{"issue":"06","key":"ref5","doi-asserted-by":"crossref","first-page":"1703","DOI":"10.3390\/cancers15061703","article-title":"Classification of chondrosarcoma: from characteristic to challenging imaging findings","volume":"15","author":"J H Kim","year":"2023","journal-title":"Cancers"},{"issue":"13","key":"ref6","doi-asserted-by":"crossref","first-page":"4415","DOI":"10.1002\/cam4.4019","article-title":"Prognostic importance of IDH mutations in chondrosarcoma: an individual patient data meta-analysis","volume":"10","author":"H G Vuong","year":"2021","journal-title":"Cancer Med"},{"issue":"03","key":"ref7","doi-asserted-by":"crossref","first-page":"520","DOI":"10.1093\/neuros\/nyx042","article-title":"Multimodality treatment of skull base chondrosarcomas: the role of histology specific treatment protocols","volume":"81","author":"S M Raza","year":"2017","journal-title":"Neurosurgery"},{"issue":"05","key":"ref8","doi-asserted-by":"crossref","first-page":"1406","DOI":"10.3171\/2025.3.JNS242797","article-title":"Impact of adjuvant radiation therapy on outcomes in grade 2 conventional chondrosarcoma","volume":"143","author":"F Rubino","year":"2025","journal-title":"J Neurosurg"},{"issue":"11","key":"ref9","doi-asserted-by":"crossref","first-page":"2457","DOI":"10.1002\/cncr.23073","article-title":"Chordoma and chondrosarcoma: similar, but quite different, skull base tumors","volume":"110","author":"K Almefty","year":"2007","journal-title":"Cancer"},{"issue":"11","key":"ref10","doi-asserted-by":"crossref","first-page":"5877","DOI":"10.3390\/ijms25115877","article-title":"Chordoma: genetics and contemporary management","volume":"25","author":"R Desai","year":"2024","journal-title":"Int J Mol Sci"},{"issue":"13","key":"ref11","doi-asserted-by":"crossref","first-page":"e107","DOI":"10.3346\/jkms.2019.34.e107","article-title":"Chordomas: histopathological study in view of anatomical location","volume":"34","author":"Y J Cha","year":"2019","journal-title":"J Korean Med Sci"},{"issue":"03","key":"ref12","doi-asserted-by":"crossref","first-page":"501","DOI":"10.1016\/j.otc.2015.02.009","article-title":"Chordoma and chondrosarcoma","volume":"48","author":"J J Van","year":"2015","journal-title":"Otolaryngol Clin N Am"},{"key":"ref13","doi-asserted-by":"crossref","first-page":"514753","DOI":"10.1155\/2014\/514753","article-title":"Brachyury: a diagnostic marker for the differential diagnosis of chordoma and hemangioblastoma versus neoplastic histological mimickers","volume":"2014","author":"V Barresi","year":"2014","journal-title":"Dis Markers"},{"issue":"02","key":"ref14","doi-asserted-by":"crossref","first-page":"157","DOI":"10.1002\/path.1969","article-title":"Brachyury, a crucial regulator of notochordal development, is a novel biomarker for chordomas","volume":"209","author":"S Vujovic","year":"2006","journal-title":"J Pathol"},{"issue":"28","key":"ref15","doi-asserted-by":"crossref","first-page":"43557","DOI":"10.18632\/oncotarget.9618","article-title":"Targeted next-generation sequencing of dedifferentiated chondrosarcoma in the skull base reveals combined TP53 and PTEN mutations with increased proliferation index, an implication for pathogenesis","volume":"7","author":"L Gao","year":"2016","journal-title":"Oncotarget"},{"issue":"15","key":"ref16","doi-asserted-by":"crossref","first-page":"3924","DOI":"10.3390\/cancers15153924","article-title":"Dedifferentiated chondrosarcoma from molecular pathology to current treatment and clinical trials","volume":"15","author":"W Zaj\u0105c","year":"2023","journal-title":"Cancers"},{"issue":"14","key":"ref17","doi-asserted-by":"crossref","first-page":"2060","DOI":"10.1016\/j.ejca.2007.06.016","article-title":"Dedifferentiated chondrosarcoma: prognostic factors and outcome from a European group","volume":"43","author":"R J Grimer","year":"2007","journal-title":"Eur J Cancer"},{"issue":"07","key":"ref18","doi-asserted-by":"crossref","first-page":"1962","DOI":"10.3390\/cancers15071962","article-title":"Chondrosarcoma resistance to radiation therapy: origins and potential therapeutic solutions","volume":"15","author":"A Gilbert","year":"2023","journal-title":"Cancers"},{"issue":"05","key":"ref19","doi-asserted-by":"crossref","first-page":"e74","DOI":"10.1055\/s-0035-1546953","article-title":"Radiation-induced intraspinal chondrosarcoma: a case report","volume":"5","author":"P Obid","year":"2015","journal-title":"Global Spine J"},{"issue":"03","key":"ref20","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1097\/IOP.0000000000000168","article-title":"Radiation-induced dedifferentiated chondrosarcoma with orbital invasion","volume":"30","author":"B W Davies","year":"2014","journal-title":"Ophthalmic Plast Reconstr Surg"},{"key":"ref21","doi-asserted-by":"crossref","first-page":"e155","DOI":"10.1055\/s-0040-1701523","article-title":"Management of recurrent or progressing skull base chondrosarcomas: predictors of long-term outcomes","volume":"82","author":"J D Breshears","year":"2021","journal-title":"J Neurol Surg B Skull Base"},{"key":"ref22","doi-asserted-by":"publisher","first-page":"746909","DOI":"10.3389\/fmed.2021.746909","article-title":"Dedifferentiated Central Chondrosarcoma: A Clinical, Histopathological, and Immunohistochemical Analysis of 57 Cases","volume":"8","author":"L H Gong","year":"2021","journal-title":"Front Med (Lausanne)"},{"issue":"14","key":"ref23","doi-asserted-by":"crossref","first-page":"3603","DOI":"10.3390\/cancers15143603","article-title":"IDH mutations in chondrosarcoma: case closed or not?","volume":"15","author":"S Venneker","year":"2023","journal-title":"Cancers"}],"container-title":["Journal of Neurological Surgery Reports"],"original-title":[],"language":"en","link":[{"URL":"http:\/\/www.thieme-connect.de\/products\/ejournals\/pdf\/10.1055\/a-2964-8969.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,10,7]],"date-time":"2026-10-07T09:10:36Z","timestamp":1791364236000},"score":1,"resource":{"primary":{"URL":"http:\/\/www.thieme-connect.de\/DOI\/DOI?10.1055\/a-2964-8969"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,10]]},"references-count":23,"journal-issue":{"issue":"04","published-online":{"date-parts":[[2026,10,6]]},"published-print":{"date-parts":[[2026,10]]}},"URL":"https:\/\/doi.org\/10.1055\/a-2964-8969","archive":["Portico","CLOCKSS"],"relation":{},"ISSN":["2193-6358","2193-6366"],"issn-type":[{"value":"2193-6358","type":"print"},{"value":"2193-6366","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,10]]}}}