{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,29]],"date-time":"2026-07-29T00:58:26Z","timestamp":1785286706188,"version":"3.55.0"},"reference-count":16,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"4","license":[{"start":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T00:00:00Z","timestamp":1785110400000},"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":[[2026,7,27]]},"abstract":"<jats:sec>\n                    <jats:title>BACKGROUND<\/jats:title>\n                    <jats:p>Spontaneous regression of meningiomas is rare, and the association between tumor growth dynamics and progressive calcification remains not well elucidated.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>OBSERVATIONS<\/jats:title>\n                    <jats:p>A 76-year-old female was incidentally noted to have a calcified posterior fossa mass during evaluation for head trauma. Retrospective review of serial noncontrast CT examinations spanning approximately 17 years revealed a biphasic volumetric course consisting an initial slow-growth phase, followed by tumor enlargement and subsequent spontaneous regression. Quantitative slice-by-slice volumetric analysis demonstrated continuous progression of intratumoral calcification across tumor evolution phases. As the tumor volume decreased, calcification progressively became the dominant lesion component. MRI performed 3 months following the latest CT study demonstrated a dural-based lesion with homogeneous enhancement and a dural tail sign, findings consistent with meningioma.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>LESSONS<\/jats:title>\n                    <jats:p>This case illustrates that meningiomas may undergo dynamic biological transitions over extended periods, including growth phases and spontaneous regression. Progressive intratumoral calcification observed throughout tumor evolution may represent a tumor aging and biological involution indicator rather than reflecting slow tumor growth.<\/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\/CASE26353\">https:\/\/thejns.org\/doi\/10.3171\/CASE26353<\/jats:ext-link>\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.3171\/case26353","type":"journal-article","created":{"date-parts":[[2026,7,22]],"date-time":"2026-07-22T00:01:27Z","timestamp":1784678487000},"source":"Crossref","is-referenced-by-count":0,"title":["Biphasic growth and subsequent spontaneous regression of posterior fossa meningioma with progressive calcification: illustrative case"],"prefix":"10.3171","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2144-663X","authenticated-orcid":true,"given":"Toshihide","family":"Takahashi","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Tsukuba Memorial Hospital, Tsukuba, Ibaraki"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kiyoyuki","family":"Yanaka","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tsukuba Memorial Hospital, Tsukuba, Ibaraki"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hitoshi","family":"Aiyama","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tsukuba Memorial Hospital, Tsukuba, Ibaraki"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saaya","family":"Maruyama","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Tsukuba Memorial Hospital, Tsukuba, Ibaraki"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nobuyuki","family":"Takahashi","sequence":"additional","affiliation":[{"name":"Department of Radiology, Tsukuba Memorial Hospital, Tsukuba, Ibaraki"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7172-7608","authenticated-orcid":true,"given":"Aiki","family":"Marushima","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Institute of Medicine, University of Tsukuba, Ibaraki, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eiichi","family":"Ishikawa","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Institute of Medicine, University of Tsukuba, Ibaraki, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"issue":"3","key":"bib1","series-title":"Biomedicines","article-title":"Meningioma: a review of epidemiology, pathology, diagnosis, treatment, and future directions","volume":"9","author":"Ogasawara","year":"2021","unstructured":"Ogasawara CPhilbrick BDAdamson DC.Meningioma: a review of epidemiology, pathology, diagnosis, treatment, and future directions. 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