{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T05:24:49Z","timestamp":1765430689093,"version":"3.46.0"},"reference-count":30,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T00:00:00Z","timestamp":1765411200000},"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>Pilocytic astrocytoma is a circumscribed central nervous system (CNS) WHO grade 1 glioma that typically arises in the cerebellum or optic\u2013hypothalamic pathways; intraventricular occurrence at or near the foramen of Monro is exceptional and can mimic a colloid cyst. Although tissue diagnosis is ultimately required, certain imaging features should keep neoplasm in the differential when a \u201ccolloid cyst\u201d is suspected. We report a 22-year-old man with a well-circumscribed, non-enhancing mass at the foramen of Monro initially favored radiologically as a colloid cyst; radiology\u2013pathology correlation after microsurgical resection established pilocytic astrocytoma with characteristic histology and a supportive immunophenotype. This case emphasizes that location and CT density are not pathognomonic and that surgical planning for equivocal lesions at the foramen of Monro should preserve a route for tissue confirmation to secure the correct diagnosis and guide management.<\/jats:p>","DOI":"10.3389\/fonc.2025.1717175","type":"journal-article","created":{"date-parts":[[2025,12,11]],"date-time":"2025-12-11T05:19:50Z","timestamp":1765430390000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Unusual localization of pilocytic astrocytoma at the foramen of Monro mimicking a colloid cyst: a case report and literature 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