{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,26]],"date-time":"2026-08-26T01:19:50Z","timestamp":1787707190320,"version":"build-2784847793"},"reference-count":15,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"8","license":[{"start":{"date-parts":[[2026,8,24]],"date-time":"2026-08-24T00:00:00Z","timestamp":1787529600000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["J Neurosurg Case Lessons"],"published-print":{"date-parts":[[2026,8,24]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND<\/jats:title>\n                    <jats:p>Delayed cerebrovascular complications after childhood cranial irradiation may include progressive vasculopathy and aneurysmal disease. However, attributing a ruptured aneurysm directly to prior irradiation can be difficult in patients with complex preexisting cerebrovascular pathology. The authors describe a diagnostic pitfall in a patient with long-standing postirradiation vasculopathy who presented with hemorrhagic distal middle cerebral artery (MCA) aneurysmal lesions.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>OBSERVATIONS<\/jats:title>\n                    <jats:p>A 51-year-old man who had undergone whole-brain irradiation for pineal germinoma at 8 years of age presented with intracerebral and subarachnoid hemorrhage. He had a long history of progressive cerebrovascular disease, including recurrent ischemic strokes, prior intracerebral hemorrhage, intracranial arterial stenosis, and a previously treated internal carotid artery aneurysm. MR angiography and initial digital subtraction angiography demonstrated a newly detected saccular distal MCA aneurysm, which was treated with coil embolization. Hematoma enlargement occurred the following day. Repeat angiography showed complete obliteration of the treated saccular aneurysm but revealed a coexisting pseudoaneurysm in the same vascular territory. Parent artery occlusion achieved definitive hemostasis without additional clinically apparent neurological deterioration.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>LESSONS<\/jats:title>\n                    <jats:p>In patients with long-standing postirradiation vasculopathy, a conspicuous saccular aneurysm may obscure a coexisting pseudoaneurysm. Repeat angiography should be considered when hemorrhage progresses despite apparent aneurysm obliteration.<\/jats:p>\n                    <jats:p>\n                      <jats:ext-link xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" ext-link-type=\"uri\" xlink:href=\"https:\/\/thejns.org\/doi\/10.3171\/CASE26561\">https:\/\/thejns.org\/doi\/10.3171\/CASE26561<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/case26561","type":"journal-article","created":{"date-parts":[[2026,8,19]],"date-time":"2026-08-19T00:01:20Z","timestamp":1787097680000},"source":"Crossref","is-referenced-by-count":0,"title":["A coexisting pseudoaneurysm hidden behind a saccular distal middle cerebral artery aneurysm in long-standing postirradiation vasculopathy: illustrative case"],"prefix":"10.3171","volume":"12","author":[{"given":"Hiroaki","family":"Matsumoto","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasunori","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0005-9993-1685","authenticated-orcid":true,"given":"Akihiro","family":"Okada","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yusuke","family":"Tomogane","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Atsushi","family":"Masuda","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2551-0504","authenticated-orcid":true,"given":"Ikuya","family":"Yamaura","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hiroaki","family":"Minami","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasuhisa","family":"Yoshida","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Cerebrovascular Research Institute, Yoshida Hospital, Kobe, Hyogo, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"4","key":"bib1","series-title":"Neurooncol Pract","first-page":"415","article-title":"Radiation-induced accelerated aging of the brain vasculature in young adult survivors of childhood brain tumors","volume":"7","author":"Remes","year":"2020","unstructured":"Remes TMSuo-Palosaari MHKoskenkorva PKTRadiation-induced accelerated aging of the brain vasculature in young adult survivors of childhood brain tumors. 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Adv Biol (Weinh). 2023;7(10):e2300179. doi:10.1002\/adbi.202300179"},{"issue":"4","key":"bib4","series-title":"Interv Neuroradiol","first-page":"448","article-title":"Radiation-induced cerebral aneurysm treated with endovascular coil embolization: a case report","volume":"20","author":"Matsumoto","year":"2014","unstructured":"Matsumoto HMinami HYamaura IYoshida Y.Radiation-induced cerebral aneurysm treated with endovascular coil embolization: a case report. Interv Neuroradiol. 2014;20(4):448-453. doi:10.15274\/INR-2014-10039"},{"issue":"4","key":"bib5","series-title":"Jpn J Stroke","first-page":"163","article-title":"A case of progressive radiation-induced cerebrovascular disease in an adult survivor of childhood cranial irradiation","volume":"48","author":"Matsumoto","year":"2026","unstructured":"Matsumoto HYoshida YOkada AA case of progressive radiation-induced cerebrovascular disease in an adult survivor of childhood cranial irradiation. Jpn J Stroke. 2026;48(4):163-169. doi:10.3995\/jstroke.11388"},{"issue":"3-4","key":"bib6","series-title":"World Neurosurg","first-page":"511","article-title":"Intracranial aneurysms in previously irradiated fields: literature review and case report","volume":"81","author":"Nanney","year":"2014","unstructured":"Nanney ADEl Tecle NEEl Ahmadieh TYIntracranial aneurysms in previously irradiated fields: literature review and case report. World Neurosurg. 2014;81(3-4):511-519. doi:10.1016\/j.wneu.2013.10.044"},{"issue":"8","key":"bib7","series-title":"AJNR Am J Neuroradiol","first-page":"1131","article-title":"Characteristics of radiation-related intracranial aneurysms: a multicenter retrospective study","volume":"43","author":"Huang","year":"2022","unstructured":"Huang ZQYang WJXiao GCharacteristics of radiation-related intracranial aneurysms: a multicenter retrospective study. AJNR Am J Neuroradiol. 2022;43(8):1131-1135. doi:10.3174\/ajnr.A7592"},{"issue":"5","key":"bib8","series-title":"Neurosurg Rev","first-page":"2995","article-title":"The prognosis and treatment effectiveness of de novo aneurysm formation after radiation therapy for brain tumor","volume":"45","author":"Shinoda","year":"2022","unstructured":"Shinoda SMuraoka SShimizu HKoketsu NAraki YSaito R.The prognosis and treatment effectiveness of de novo aneurysm formation after radiation therapy for brain tumor. Neurosurg Rev. 2022;45(5):2995-3002. doi:10.1007\/s10143-022-01820-5"},{"key":"bib9","series-title":"Interv Neuroradiol","first-page":"15910199251372511","article-title":"Radiation-associated intracranial aneurysms: a systematic review of clinical presentation, morphology, and treatment outcomes","author":"Barba","year":"2025","unstructured":"Barba MCMuni RSardaro ARadiation-associated intracranial aneurysms: a systematic review of clinical presentation, morphology, and treatment outcomes. 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