Adult Thoracic Intramedullary Pilocytic Astrocytoma With Prominent Glomeruloid Microvascular Proliferation Diagnosed by Integrated Molecular Analysis A Case Report

Adult Thoracic Intramedullary Pilocytic Astrocytoma With Prominent Glomeruloid Microvascular Proliferation Diagnosed by Integrated Molecular Analysis A Case Report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Adult Thoracic Intramedullary Pilocytic Astrocytoma With Prominent Glomeruloid Microvascular Proliferation Diagnosed by Integrated Molecular Analysis A Case Report Xueyi Li, Shihao Wang, Tingting Sun, Yisha Guo, Qilong Hu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8542411/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 15 You are reading this latest preprint version Abstract Background: Pilocytic astrocytoma (PA) is a circumscribed, World Health Organization (WHO) grade 1 glioma that predominantly affects children and is rare in the adult spinal cord. Diagnostic difficulty arises when adult spinal PAs exhibit radiological or histopathological features typically associated with high-grade gliomas, particularly prominent microvascular proliferation, which may result in tumor overgrading and overtreatment. Case Description: We report a 20-year-old male presenting with progressive thoracic myelopathy and evolving paraplegia. Magnetic resonance imaging demonstrated diffuse intramedullary spinal cord expansion from T2 to T9 with a focal, avidly ring-enhancing lesion at T6–7, raising concern for a high-grade intramedullary glioma. Surgical resection was undertaken, guided by the presumed malignant nature of the lesion. Histopathology revealed classic pilocytic architecture with abundant Rosenthal fibers but also striking glomeruloid microvascular proliferation. Integrated molecular analysis showed retained H3K27me3 expression, wild-type BRAF V600E, and absence of TERT promoter mutation, establishing a final diagnosis of pilocytic astrocytoma, CNS WHO grade 1. Postoperatively, the patient developed complete spinal cord injury but achieved functional independence in wheelchair mobility and autonomous bladder management through structured rehabilitation. Conclusion: This case highlights a critical diagnostic pitfall in adult intramedullary spinal tumors: microvascular proliferation in pilocytic astrocytoma does not equate to malignant biological behavior. Integrated molecular diagnostics—particularly assessment of H3K27 status—are essential to avoid misclassification, inappropriate treatment escalation, and irreversible neurological morbidity. Pilocytic astrocytoma Intramedullary spinal cord tumor Glomeruloid microvascular proliferation H3K27me3 Integrated molecular diagnosis Adult spinal glioma Figures Figure 1 Figure 2 Introduction Intramedullary spinal cord tumors (IMSCTs) constitute approximately 2–4% of central nervous system neoplasms and present distinct diagnostic and therapeutic challenges due to their eloquent location and limited surgical corridors [ 1 ]. Tumor spectrum varies significantly with age: while pilocytic astrocytoma (PA) is the most common pediatric glioma, adult IMSCTs are dominated by ependymomas and diffuse astrocytic tumors [ 2 ]. PA is classified as a circumscribed astrocytic glioma, CNS WHO grade 1, and generally carries a favorable biological prognosis [ 3 ]. However, adult spinal PAs are rare and frequently exhibit atypical radiological or histological features, including long-segment cord expansion, heterogeneous or ring-like enhancement, and prominent vascular proliferation, which may mimic high-grade gliomas [ 4 , 5 ]. These features create a substantial risk of overgrading and overtreatment. In the 2021 WHO Classification, integrated molecular diagnosis has become essential, particularly to distinguish PA from diffuse midline glioma (DMG), H3 K27-altered, a WHO grade 4 tumor with dismal prognosis that frequently involves the spinal cord [ 6 , 7 ]. We present a young adult with thoracic intramedullary PA showing prominent glomeruloid microvascular proliferation and aggressive imaging features, illustrating a critical diagnostic pitfall and its impact on surgical strategy and neurological outcome. Case Presentation A 20-year-old male presented with a 4-month history of progressive bilateral lower-extremity numbness and weakness. Preoperatively, left lower-limb weakness was evident, while right-sided strength was relatively preserved. Thoracic MRI revealed diffuse intramedullary cord expansion from T2 to T9, with multiple ill-defined patchy enhancing foci and a focal, avidly ring-enhancing lesion at the T6–7 level measuring approximately 25 × 8 × 7 mm (Fig. 1 ). These findings raised strong suspicion for an infiltrative high-grade intramedullary glioma, with ependymoma also considered in the differential diagnosis [ 4 , 8 ]. The patient underwent T6–7 laminectomy and midline myelotomy for tumor resection. Intraoperatively,the lesion appeared intramedullary with moderate vascularity and poorly defined margins. Given the multifocal intramedullary enhancement on MRI and concern for malignant biological behavior, an expanded gross total resection was pursued to minimize the risk of residual disease and recurrence. Histopathological examination demonstrated a biphasic glial neoplasm composed of compact bipolar cells with abundant Rosenthal fibers and loose microcystic areas, consistent with pilocytic morphology. Notably, there was prominent glomeruloid microvascular proliferation and endothelial hyperplasia, features typically associated with high-grade astrocytic tumors [ 5 , 9 ]. Immunohistochemistry showed diffuse positivity for GFAP, Olig-2, SOX-2, and S-100. The Ki-67 labeling index was low (~ 2%). ATRX expression was retained, p53 showed a wild-type pattern, and nuclear H3K27me3 expression was preserved. Molecular testing revealed wild-type BRAF V600E and absence of TERT promoter mutation. Mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) were intact. Based on integrated histological and molecular findings, the final diagnosis was pilocytic astrocytoma, CNS WHO grade 1. Postoperatively, the patient developed complete paraplegia with sensory loss below T7 and was classified as ASIA Impairment Scale grade A. Follow-up MRI at one month showed no evidence of residual or recurrent tumor. With structured rehabilitation, the patient achieved independent wheelchair mobility and autonomous bladder management, despite persistent motor deficits (Table 1 ). Table 1 Timeline of Clinical Course Time point Event Aug 2025 Left lower-limb numbness and mild weakness developed Sep 2025 Lumbar MRI and knee examination showed no abnormalities Oct 2025 Progressive gait difficulty; unable to climb stairs Oct 2025 Thoracic spinal MRI revealed intramedullary lesion at T2–T9 Oct 31, 2025 T6–7 intramedullary lesion resection performed Post-op day 1 Complete paraplegia and bowel/bladder dysfunction noted Nov 2025 Pathology suggested pilocytic astrocytoma Nov 2025 Molecular testing showed BRAF V600E wild-type, TERT wild-type Nov–Dec 2025 Inpatient rehabilitation initiated 1 month post-op ASIA grade A; independent wheelchair transfer achieved Follow-up MRI No evidence of tumor recurrence Discussion This case underscores several critical challenges in the diagnosis and management of adult intramedullary spinal PA. First, extensive longitudinal involvement and ring-enhancing nodules may closely resemble malignant intramedullary gliomas on MRI, particularly in adolescents and young adults [ 4 , 10 ]. Such imaging features frequently prompt aggressive oncologic strategies. Second, the presence of glomeruloid microvascular proliferation represents a major histopathological pitfall. In diffuse astrocytic gliomas, this feature is diagnostic of CNS WHO grade 4 disease. However, vascular proliferation is a recognized, non-anaplastic feature in PA and does not independently confer malignant biological behavior or poor prognosis [ 5 , 9 , 11 ]. In this case, the low proliferative index and classic pilocytic architecture contrasted sharply with the alarming vascular morphology. Crucially, molecular exclusion of DMG, H3 K27-altered, is mandatory in adult spinal cord tumors [ 6 , 7 ]. Retained H3K27me3 expression in this patient was pivotal in excluding DMG, which may occasionally display deceptively low-grade morphology yet follows an aggressive clinical course [ 12 ]. The absence of BRAF V600E and TERT promoter mutations further supported a low-grade, fusion-driven biology typical of PA [ 3 , 13 ]. Importantly, this case illustrates how diagnostic uncertainty can influence surgical decision-making and functional outcome. The presumption of malignancy—driven by aggressive imaging and vascular histology—led to an expanded resection strategy aimed at oncologic control. Subsequent integrated molecular diagnosis reclassified the lesion as benign, revealing a discordance between presumed and actual tumor biology. While preoperative neurological status remains the strongest predictor of postoperative function in IMSCTs [ 14 ], treatment intensity shaped by overestimation of malignancy may contribute to catastrophic neurological sequelae. Despite irreversible motor deficits, accurate final diagnosis spared the patient from unnecessary adjuvant radiotherapy or chemotherapy and enabled a rehabilitation-focused survivorship approach. Functional independence, including autonomous bladder management, represents a clinically meaningful outcome that underscores the importance of balancing oncologic ambition with neurological preservation in molecularly defined low-grade spinal tumors [ 15 ]. Declarations Funding This work was supported by grants from the National Key Clinical Specialty Discipline Construction Project of China(Z155080000004), the Shanghai Research Center of Rehabilitation Medicine (Top Priority Research Center of Shanghai)(2023ZZ02027), the Shanghai Hospital Development Center Foundation—Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance(SHDC22023304), and Shanghai Hospital Development Center Foundation—Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance(SHDC22026304). conflict of interest The authors have no conflict of interest related to this publication. Author Contributions Xueyi Li: conceptualization, writing – original draft. Shihao Wang&Tingting Sun: literature searches and analyses. Yisha Guo: designed the structure of the manuscript. Qilong Hu: the improvement of the manuscript. All authors have approved the final version of the manuscript. Ethics approval and consent to participate All procedures performed in this study were approved by the Institutional Review Board of Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center) Medical Ethics Committee. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). Informed consent to participate was obtained from the patient. Data Availability Statement All data generated or analysed during this study are included in this published article and its supplementary information files. Additional details are available from the corresponding author on reasonable request. Consent to publish Written informed consent for publication of this case report and any accompanying images was obtained from the patient. Clinical trial number: not applicable. References McFaline-Figueroa JR. Spinal Cord Neoplasms. Continuum (Minneapolis Minn). 2024;30(1):99–118. https://doi.org/10.1212/CON.0000000000001375 . Noureldine MHA, Shimony N, Jallo GI. Malignant Spinal Tumors. Adv Exp Med Biol. 2023;1405:565–81. https://doi.org/10.1007/978-3-031-23705-8_22 . Pizzimenti C, Fiorentino V, Germanò A, Martini M, Ieni A, Tuccari G. Pilocytic astrocytoma: The paradigmatic entity in low-grade gliomas (Review). Oncol Lett. 2024;27(4):146. https://doi.org/10.3892/ol.2024.14279 . Shah LM, Salzman KL. Conventional and Advanced Imaging of Spinal Cord Tumors. Neuroimaging Clin N Am. 2023;33(3):389–406. https://doi.org/10.1016/j.nic.2023.03.001 . Alturkustani M. Infiltration in Pilocytic Astrocytoma: A Diagnostic Pitfall. Cureus. 2022;14(8):e27940. https://doi.org/10.7759/cureus.27940 . Wang YZ, Zhang YW, Liu WH, Chai RC, Cao R, Wang B, An SY, Jiang WJ, Xu YL, Yang J, Jia WQ. Spinal Cord Diffuse Midline Gliomas With H3 K27m-Mutant: Clinicopathological Features and Prognosis. Neurosurgery. 2021;89(2):300–7. https://doi.org/10.1093/neuros/nyab174 . Yang QY, Li MN, Chen TY, Liu C, Li X, Shi ZM, Pan MH. (2023). Zhonghua bing li xue za zhi = Chinese journal of pathology , 52 (4), 376–383. https://doi.org/10.3760/cma.j.cn112151-20220926-00810 Anghileri E, Broggi M, Mazzapicchi E, Farinotti M, Botturi A, Tramacere I, Marchetti M. Therapeutic Approaches in Adult Primary Spinal Cord Astrocytoma: A Systematic Review. Cancers. 2022;14(5):1292. https://doi.org/10.3390/cancers14051292 . Trifoi SV, Biswas S, Szylak R, Carleton-Bland N. Spinal cord anaplastic Pilocytic Astrocytoma - two stage resection with elsberg and beer technique. Case report and literature review. Br J Neurosurg. 2025;39(5):690–4. https://doi.org/10.1080/02688697.2024.2357349 . Kiani Salmi S, Dehghanian A, Taherifard A, Dehghan A. Holocord pilocytic astrocytoma in a young woman with intracranial extension: case report and review of the MRI characteristics. Spinal cord Ser cases. 2024;10(1):43. https://doi.org/10.1038/s41394-024-00656-z . Gramatzki D, Felsberg J, Hentschel B, Bähr O, Westphal M, Schackert G, Tonn JC, Herrlinger U, Loeffler M, Pietsch T, Steinbach JP, Reifenberger G, Roth P, Weller M. Chemotherapy for adult patients with spinal cord gliomas. Neuro-oncology Pract. 2021;8(4):475–84. https://doi.org/10.1093/nop/npab017 . Palpan Flores A, Rodríguez Domínguez V, Esteban Rodriguez I, Román de Aragón M, Zamarrón Pérez Á. H3K27M-mutant glioma in thoracic spinal cord and conus medullaris with pilocytic astrocytoma morphology: case report and review of the literature. Br J Neurosurg. 2024;38(4):1020–6. https://doi.org/10.1080/02688697.2021.1988054 . Misove A, Vicha A, Broz P, Vanova K, Sumerauer D, Stolova L, Sramkova L, Koblizek M, Zamecnik J, Kyncl M, Holubova Z, Liby P, Taborsky J, Benes V 3rd, Pernikova I, Jones DTW, Sill M, Stancokova T, Krskova L, Zapotocky M. Integrated genomic analysis reveals actionable targets in pediatric spinal cord low-grade gliomas. Acta Neuropathol Commun. 2022;10(1):143. https://doi.org/10.1186/s40478-022-01446-0 . Baig Mirza A, Gebreyohanes A, Knight J, Bartram J, Vastani A, Kalaitzoglou D, Lavrador JP, Kailaya-Vasan A, Maratos E, Bell D, Thomas N, Gullan R, Malik I, Grahovac G. Prognostic factors for surgically managed intramedullary spinal cord tumours: a single-centre case series. Acta Neurochir. 2022;164(10):2605–22. https://doi.org/10.1007/s00701-022-05304-9 . Al-Mistarehi AH, Zaitoun KJ, Javed S, Xia Y, Hersh A, Ghaith AK, Weber-Levine C, Jiang K, Khan M, Mendelson B, Ksabi N, Sciubba DM, Gokaslan ZL, Jallo GI, Wolinsky JP, Theodore N, Lubelski D. Survival and Functional Outcomes Following Surgical Resection of Intramedullary Spinal Cord Tumors: A Series of 253 Patients over 22 Years. Cancers. 2025;17(13):2112. https://doi.org/10.3390/cancers17132112 . Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 24 Feb, 2026 Reviewers agreed at journal 20 Feb, 2026 Reviewers agreed at journal 20 Feb, 2026 Reviewers agreed at journal 18 Feb, 2026 Reviews received at journal 18 Feb, 2026 Reviewers agreed at journal 18 Feb, 2026 Reviewers agreed at journal 12 Feb, 2026 Reviews received at journal 24 Jan, 2026 Reviewers agreed at journal 23 Jan, 2026 Reviewers agreed at journal 22 Jan, 2026 Reviewers invited by journal 22 Jan, 2026 Editor invited by journal 22 Jan, 2026 Editor assigned by journal 22 Jan, 2026 Submission checks completed at journal 20 Jan, 2026 First submitted to journal 20 Jan, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8542411","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":579884793,"identity":"38f2fde0-2d7a-400e-a06a-ee55c236d73b","order_by":0,"name":"Xueyi Li","email":"","orcid":"","institution":"Affiliated Yangzhi Rehabilitation Hospital of Tongji University, Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Xueyi","middleName":"","lastName":"Li","suffix":""},{"id":579884795,"identity":"23126084-ffc4-4df3-9ece-862138ed2173","order_by":1,"name":"Shihao Wang","email":"","orcid":"","institution":"Affiliated Yangzhi Rehabilitation Hospital of Tongji University, Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Shihao","middleName":"","lastName":"Wang","suffix":""},{"id":579884796,"identity":"28dda4d3-550f-4a77-8bf3-48bf26b5ee43","order_by":2,"name":"Tingting Sun","email":"","orcid":"","institution":"Affiliated Yangzhi Rehabilitation Hospital of Tongji University, Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Tingting","middleName":"","lastName":"Sun","suffix":""},{"id":579884798,"identity":"1f3fb6da-e3e3-4036-80ee-1f9b81f33d20","order_by":3,"name":"Yisha Guo","email":"","orcid":"","institution":"Affiliated Yangzhi Rehabilitation Hospital of Tongji University, Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":false,"prefix":"","firstName":"Yisha","middleName":"","lastName":"Guo","suffix":""},{"id":579884800,"identity":"5ea7c1e5-439e-4b3f-974c-8a4c059a3d99","order_by":4,"name":"Qilong Hu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAoElEQVRIiWNgGAWjYBACAwbmNgaGCgk5eRK0MAK1nLEwNmwgSQtjW0UiwwFitZizJ7Y9/DlPIoGxgfnhoxvEaLHsedhuILlNIo+dgc3YOIcoh91IbJMw3CZRzNjAwyZNvJbEORKJDQdI0nKwgSQtZx62STYckzA2bCbaL8eTj0n+qKmTk2dvfviYKC0MDAlQmpk45chaRsEoGAWjYBTgAgDvyi/D7jURRAAAAABJRU5ErkJggg==","orcid":"","institution":"Affiliated Yangzhi Rehabilitation Hospital of Tongji University, Shanghai Yangzhi Rehabilitation Hospital","correspondingAuthor":true,"prefix":"","firstName":"Qilong","middleName":"","lastName":"Hu","suffix":""}],"badges":[],"createdAt":"2026-01-07 14:08:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8542411/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8542411/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":101273681,"identity":"a0ef8a63-0741-47d2-ac35-a16fbe6cad18","added_by":"auto","created_at":"2026-01-28 03:07:15","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":423296,"visible":true,"origin":"","legend":"\u003cp\u003ePreoperative contrast-enhanced MRI of the thoracic spine.(A) sagittal contrast-enhanced T1-weighted MRI demonstrating diffuse intramedullary spinal cord expansion from T2 to T9, with a focal avidly ring-enhancing lesion at the T6–7 level and multiple ill-defined patchy intramedullary enhancing foci. (B) Axial T1-weighted post-contrast image confirms the intramedullary location with prominent peripheral ring enhancement, mimicking high-grade glioma.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-8542411/v1/d9a960b0f9f74ebc5af7736c.png"},{"id":101273682,"identity":"53b62c25-64be-499e-9267-3844a449531f","added_by":"auto","created_at":"2026-01-28 03:07:15","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":495085,"visible":true,"origin":"","legend":"\u003cp\u003ePostoperative follow-up MRI at 1 month. (A) Sagittal T1 + C and (B) Axial T1 + C images demonstrate complete resolution of the enhancing lesion at T6–7, confirming gross total resection with no evidence of early tumor recurrence.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-8542411/v1/d820e0d97897db0ba913b93d.png"},{"id":101942693,"identity":"54f94ce5-8617-427f-a577-a7169e995381","added_by":"auto","created_at":"2026-02-05 09:34:06","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1904688,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8542411/v1/72a617d9-158e-4c94-a6f6-9de2d08b31d7.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Adult Thoracic Intramedullary Pilocytic Astrocytoma With Prominent Glomeruloid Microvascular Proliferation Diagnosed by Integrated Molecular Analysis A Case Report","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntramedullary spinal cord tumors (IMSCTs) constitute approximately 2\u0026ndash;4% of central nervous system neoplasms and present distinct diagnostic and therapeutic challenges due to their eloquent location and limited surgical corridors [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Tumor spectrum varies significantly with age: while pilocytic astrocytoma (PA) is the most common pediatric glioma, adult IMSCTs are dominated by ependymomas and diffuse astrocytic tumors [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePA is classified as a circumscribed astrocytic glioma, CNS WHO grade 1, and generally carries a favorable biological prognosis [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. However, adult spinal PAs are rare and frequently exhibit atypical radiological or histological features, including long-segment cord expansion, heterogeneous or ring-like enhancement, and prominent vascular proliferation, which may mimic high-grade gliomas [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. These features create a substantial risk of overgrading and overtreatment.\u003c/p\u003e \u003cp\u003eIn the 2021 WHO Classification, integrated molecular diagnosis has become essential, particularly to distinguish PA from diffuse midline glioma (DMG), H3 K27-altered, a WHO grade 4 tumor with dismal prognosis that frequently involves the spinal cord [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. We present a young adult with thoracic intramedullary PA showing prominent glomeruloid microvascular proliferation and aggressive imaging features, illustrating a critical diagnostic pitfall and its impact on surgical strategy and neurological outcome.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 20-year-old male presented with a 4-month history of progressive bilateral lower-extremity numbness and weakness. Preoperatively, left lower-limb weakness was evident, while right-sided strength was relatively preserved. Thoracic MRI revealed diffuse intramedullary cord expansion from T2 to T9, with multiple ill-defined patchy enhancing foci and a focal, avidly ring-enhancing lesion at the T6\u0026ndash;7 level measuring approximately 25 \u0026times; 8 \u0026times; 7 mm (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e). These findings raised strong suspicion for an infiltrative high-grade intramedullary glioma, with ependymoma also considered in the differential diagnosis [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe patient underwent T6\u0026ndash;7 laminectomy and midline myelotomy for tumor resection. Intraoperatively,the lesion appeared intramedullary with moderate vascularity and poorly defined margins. Given the multifocal intramedullary enhancement on MRI and concern for malignant biological behavior, an expanded gross total resection was pursued to minimize the risk of residual disease and recurrence.\u003c/p\u003e \u003cp\u003eHistopathological examination demonstrated a biphasic glial neoplasm composed of compact bipolar cells with abundant Rosenthal fibers and loose microcystic areas, consistent with pilocytic morphology. Notably, there was prominent glomeruloid microvascular proliferation and endothelial hyperplasia, features typically associated with high-grade astrocytic tumors [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Immunohistochemistry showed diffuse positivity for GFAP, Olig-2, SOX-2, and S-100. The Ki-67 labeling index was low (~\u0026thinsp;2%). ATRX expression was retained, p53 showed a wild-type pattern, and nuclear H3K27me3 expression was preserved.\u003c/p\u003e \u003cp\u003eMolecular testing revealed wild-type BRAF V600E and absence of TERT promoter mutation. Mismatch repair proteins (MLH1, MSH2, MSH6, PMS2) were intact. Based on integrated histological and molecular findings, the final diagnosis was pilocytic astrocytoma, CNS WHO grade 1.\u003c/p\u003e \u003cp\u003ePostoperatively, the patient developed complete paraplegia with sensory loss below T7 and was classified as ASIA Impairment Scale grade A. Follow-up MRI at one month showed no evidence of residual or recurrent tumor. With structured rehabilitation, the patient achieved independent wheelchair mobility and autonomous bladder management, despite persistent motor deficits (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eTimeline of Clinical Course\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTime point\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eEvent\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAug 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeft lower-limb numbness and mild weakness developed\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSep 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLumbar MRI and knee examination showed no abnormalities\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOct 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eProgressive gait difficulty; unable to climb stairs\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOct 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThoracic spinal MRI revealed intramedullary lesion at T2\u0026ndash;T9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOct 31, 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eT6\u0026ndash;7 intramedullary lesion resection performed\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePost-op day 1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eComplete paraplegia and bowel/bladder dysfunction noted\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNov 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePathology suggested pilocytic astrocytoma\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNov 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMolecular testing showed BRAF V600E wild-type, TERT wild-type\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNov\u0026ndash;Dec 2025\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eInpatient rehabilitation initiated\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e1 month post-op\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eASIA grade A; independent wheelchair transfer achieved\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFollow-up MRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNo evidence of tumor recurrence\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case underscores several critical challenges in the diagnosis and management of adult intramedullary spinal PA. First, extensive longitudinal involvement and ring-enhancing nodules may closely resemble malignant intramedullary gliomas on MRI, particularly in adolescents and young adults [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Such imaging features frequently prompt aggressive oncologic strategies.\u003c/p\u003e \u003cp\u003eSecond, the presence of glomeruloid microvascular proliferation represents a major histopathological pitfall. In diffuse astrocytic gliomas, this feature is diagnostic of CNS WHO grade 4 disease. However, vascular proliferation is a recognized, non-anaplastic feature in PA and does not independently confer malignant biological behavior or poor prognosis [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. In this case, the low proliferative index and classic pilocytic architecture contrasted sharply with the alarming vascular morphology.\u003c/p\u003e \u003cp\u003eCrucially, molecular exclusion of DMG, H3 K27-altered, is mandatory in adult spinal cord tumors [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Retained H3K27me3 expression in this patient was pivotal in excluding DMG, which may occasionally display deceptively low-grade morphology yet follows an aggressive clinical course [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The absence of BRAF V600E and TERT promoter mutations further supported a low-grade, fusion-driven biology typical of PA [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eImportantly, this case illustrates how diagnostic uncertainty can influence surgical decision-making and functional outcome. The presumption of malignancy\u0026mdash;driven by aggressive imaging and vascular histology\u0026mdash;led to an expanded resection strategy aimed at oncologic control. Subsequent integrated molecular diagnosis reclassified the lesion as benign, revealing a discordance between presumed and actual tumor biology. While preoperative neurological status remains the strongest predictor of postoperative function in IMSCTs [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e], treatment intensity shaped by overestimation of malignancy may contribute to catastrophic neurological sequelae.\u003c/p\u003e \u003cp\u003eDespite irreversible motor deficits, accurate final diagnosis spared the patient from unnecessary adjuvant radiotherapy or chemotherapy and enabled a rehabilitation-focused survivorship approach. Functional independence, including autonomous bladder management, represents a clinically meaningful outcome that underscores the importance of balancing oncologic ambition with neurological preservation in molecularly defined low-grade spinal tumors [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis work was supported by grants from the National Key Clinical Specialty Discipline Construction Project of China(Z155080000004), the Shanghai Research Center of Rehabilitation Medicine\u003c/p\u003e\n\u003cp\u003e(Top Priority Research Center of Shanghai)(2023ZZ02027), the Shanghai Hospital Development Center Foundation\u0026mdash;Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance(SHDC22023304), and Shanghai Hospital Development Center Foundation\u0026mdash;Shanghai Municipal Hospital Rehabilitation Medicine Specialty Alliance(SHDC22026304).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003econflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors have no conflict of interest related to this publication.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eXueyi Li:\u003c/strong\u003e conceptualization, writing \u0026ndash; original draft. \u003cstrong\u003eShihao Wang\u0026amp;Tingting Sun:\u003c/strong\u003e literature searches and analyses. \u003cstrong\u003eYisha Guo:\u003c/strong\u003e designed the structure of the manuscript. \u003cstrong\u003eQilong Hu:\u003c/strong\u003e the improvement of the manuscript. All authors have approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures performed in this study were approved by the Institutional Review Board of Shanghai Yangzhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center) Medical Ethics Committee. The study was conducted in accordance with the Declaration of Helsinki (as revised in 2013). Informed consent to participate was obtained from the patient.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analysed during this study are included in this published article and its supplementary information files. Additional details are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to publish\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWritten informed consent for publication of this case report and any accompanying images was obtained from the patient.\u003c/p\u003e\n\u003cp\u003eClinical trial number: not applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eMcFaline-Figueroa JR. Spinal Cord Neoplasms. Continuum (Minneapolis Minn). 2024;30(1):99\u0026ndash;118. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1212/CON.0000000000001375\u003c/span\u003e\u003cspan address=\"10.1212/CON.0000000000001375\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eNoureldine MHA, Shimony N, Jallo GI. Malignant Spinal Tumors. Adv Exp Med Biol. 2023;1405:565\u0026ndash;81. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/978-3-031-23705-8_22\u003c/span\u003e\u003cspan address=\"10.1007/978-3-031-23705-8_22\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePizzimenti C, Fiorentino V, German\u0026ograve; A, Martini M, Ieni A, Tuccari G. Pilocytic astrocytoma: The paradigmatic entity in low-grade gliomas (Review). Oncol Lett. 2024;27(4):146. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3892/ol.2024.14279\u003c/span\u003e\u003cspan address=\"10.3892/ol.2024.14279\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShah LM, Salzman KL. Conventional and Advanced Imaging of Spinal Cord Tumors. Neuroimaging Clin N Am. 2023;33(3):389\u0026ndash;406. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.nic.2023.03.001\u003c/span\u003e\u003cspan address=\"10.1016/j.nic.2023.03.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlturkustani M. Infiltration in Pilocytic Astrocytoma: A Diagnostic Pitfall. Cureus. 2022;14(8):e27940. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.7759/cureus.27940\u003c/span\u003e\u003cspan address=\"10.7759/cureus.27940\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eWang YZ, Zhang YW, Liu WH, Chai RC, Cao R, Wang B, An SY, Jiang WJ, Xu YL, Yang J, Jia WQ. Spinal Cord Diffuse Midline Gliomas With H3 K27m-Mutant: Clinicopathological Features and Prognosis. Neurosurgery. 2021;89(2):300\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/neuros/nyab174\u003c/span\u003e\u003cspan address=\"10.1093/neuros/nyab174\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang QY, Li MN, Chen TY, Liu C, Li X, Shi ZM, Pan MH. (2023). \u003cem\u003eZhonghua bing li xue za zhi\u0026thinsp;=\u0026thinsp;Chinese journal of pathology\u003c/em\u003e, \u003cem\u003e52\u003c/em\u003e(4), 376\u0026ndash;383. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3760/cma.j.cn112151-20220926-00810\u003c/span\u003e\u003cspan address=\"10.3760/cma.j.cn112151-20220926-00810\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAnghileri E, Broggi M, Mazzapicchi E, Farinotti M, Botturi A, Tramacere I, Marchetti M. Therapeutic Approaches in Adult Primary Spinal Cord Astrocytoma: A Systematic Review. Cancers. 2022;14(5):1292. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/cancers14051292\u003c/span\u003e\u003cspan address=\"10.3390/cancers14051292\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eTrifoi SV, Biswas S, Szylak R, Carleton-Bland N. Spinal cord anaplastic Pilocytic Astrocytoma - two stage resection with elsberg and beer technique. Case report and literature review. Br J Neurosurg. 2025;39(5):690\u0026ndash;4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/02688697.2024.2357349\u003c/span\u003e\u003cspan address=\"10.1080/02688697.2024.2357349\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKiani Salmi S, Dehghanian A, Taherifard A, Dehghan A. Holocord pilocytic astrocytoma in a young woman with intracranial extension: case report and review of the MRI characteristics. Spinal cord Ser cases. 2024;10(1):43. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1038/s41394-024-00656-z\u003c/span\u003e\u003cspan address=\"10.1038/s41394-024-00656-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGramatzki D, Felsberg J, Hentschel B, B\u0026auml;hr O, Westphal M, Schackert G, Tonn JC, Herrlinger U, Loeffler M, Pietsch T, Steinbach JP, Reifenberger G, Roth P, Weller M. Chemotherapy for adult patients with spinal cord gliomas. Neuro-oncology Pract. 2021;8(4):475\u0026ndash;84. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1093/nop/npab017\u003c/span\u003e\u003cspan address=\"10.1093/nop/npab017\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePalpan Flores A, Rodr\u0026iacute;guez Dom\u0026iacute;nguez V, Esteban Rodriguez I, Rom\u0026aacute;n de Arag\u0026oacute;n M, Zamarr\u0026oacute;n P\u0026eacute;rez \u0026Aacute;. H3K27M-mutant glioma in thoracic spinal cord and conus medullaris with pilocytic astrocytoma morphology: case report and review of the literature. Br J Neurosurg. 2024;38(4):1020\u0026ndash;6. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1080/02688697.2021.1988054\u003c/span\u003e\u003cspan address=\"10.1080/02688697.2021.1988054\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMisove A, Vicha A, Broz P, Vanova K, Sumerauer D, Stolova L, Sramkova L, Koblizek M, Zamecnik J, Kyncl M, Holubova Z, Liby P, Taborsky J, Benes V 3rd, Pernikova I, Jones DTW, Sill M, Stancokova T, Krskova L, Zapotocky M. Integrated genomic analysis reveals actionable targets in pediatric spinal cord low-grade gliomas. Acta Neuropathol Commun. 2022;10(1):143. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1186/s40478-022-01446-0\u003c/span\u003e\u003cspan address=\"10.1186/s40478-022-01446-0\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaig Mirza A, Gebreyohanes A, Knight J, Bartram J, Vastani A, Kalaitzoglou D, Lavrador JP, Kailaya-Vasan A, Maratos E, Bell D, Thomas N, Gullan R, Malik I, Grahovac G. Prognostic factors for surgically managed intramedullary spinal cord tumours: a single-centre case series. Acta Neurochir. 2022;164(10):2605\u0026ndash;22. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1007/s00701-022-05304-9\u003c/span\u003e\u003cspan address=\"10.1007/s00701-022-05304-9\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAl-Mistarehi AH, Zaitoun KJ, Javed S, Xia Y, Hersh A, Ghaith AK, Weber-Levine C, Jiang K, Khan M, Mendelson B, Ksabi N, Sciubba DM, Gokaslan ZL, Jallo GI, Wolinsky JP, Theodore N, Lubelski D. Survival and Functional Outcomes Following Surgical Resection of Intramedullary Spinal Cord Tumors: A Series of 253 Patients over 22 Years. Cancers. 2025;17(13):2112. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/cancers17132112\u003c/span\u003e\u003cspan address=\"10.3390/cancers17132112\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"discover-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dion","sideBox":"Learn more about [Discover Oncology](https://www.springer.com/12672)","snPcode":"","submissionUrl":"","title":"Discover Oncology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Pilocytic astrocytoma, Intramedullary spinal cord tumor, Glomeruloid microvascular proliferation, H3K27me3, Integrated molecular diagnosis, Adult spinal glioma","lastPublishedDoi":"10.21203/rs.3.rs-8542411/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8542411/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground:\u003cbr\u003e\nPilocytic astrocytoma (PA) is a circumscribed, World Health Organization (WHO) grade 1 glioma that predominantly affects children and is rare in the adult spinal cord. Diagnostic difficulty arises when adult spinal PAs exhibit radiological or histopathological features typically associated with high-grade gliomas, particularly prominent microvascular proliferation, which may result in tumor overgrading and overtreatment.\u003c/p\u003e\n\u003cp\u003eCase Description:\u003cbr\u003e\nWe report a 20-year-old male presenting with progressive thoracic myelopathy and evolving paraplegia. Magnetic resonance imaging demonstrated diffuse intramedullary spinal cord expansion from T2 to T9 with a focal, avidly ring-enhancing lesion at T6–7, raising concern for a high-grade intramedullary glioma. Surgical resection was undertaken, guided by the presumed malignant nature of the lesion. Histopathology revealed classic pilocytic architecture with abundant Rosenthal fibers but also striking glomeruloid microvascular proliferation. Integrated molecular analysis showed retained H3K27me3 expression, wild-type BRAF V600E, and absence of TERT promoter mutation, establishing a final diagnosis of pilocytic astrocytoma, CNS WHO grade 1. Postoperatively, the patient developed complete spinal cord injury but achieved functional independence in wheelchair mobility and autonomous bladder management through structured rehabilitation.\u003c/p\u003e\n\u003cp\u003eConclusion:\u003cbr\u003e\nThis case highlights a critical diagnostic pitfall in adult intramedullary spinal tumors: microvascular proliferation in pilocytic astrocytoma does not equate to malignant biological behavior. Integrated molecular diagnostics—particularly assessment of H3K27 status—are essential to avoid misclassification, inappropriate treatment escalation, and irreversible neurological morbidity.\u003c/p\u003e","manuscriptTitle":"Adult Thoracic Intramedullary Pilocytic Astrocytoma With Prominent Glomeruloid Microvascular Proliferation Diagnosed by Integrated Molecular Analysis A Case Report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-01-28 03:07:10","doi":"10.21203/rs.3.rs-8542411/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2026-02-24T10:18:10+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"316440782329884464832203733090656838906","date":"2026-02-20T06:54:08+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"64491633566925984484152773969418925784","date":"2026-02-20T06:38:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"139174687311792951334487252329255122097","date":"2026-02-18T10:03:26+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-02-18T08:17:20+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"242216551266542909563874505012205088619","date":"2026-02-18T07:44:15+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"139793197608605813820248485345033938601","date":"2026-02-12T05:11:52+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-01-24T18:28:33+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"138838019608062137069422129835226573580","date":"2026-01-23T08:19:57+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"141407173572331985808572546539982989239","date":"2026-01-22T17:31:50+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-01-22T13:42:31+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2026-01-22T09:40:56+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-01-22T06:45:24+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-01-20T10:01:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Discover Oncology","date":"2026-01-20T09:40:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"discover-oncology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"dion","sideBox":"Learn more about [Discover Oncology](https://www.springer.com/12672)","snPcode":"","submissionUrl":"","title":"Discover Oncology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Discover Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fa0ef1e7-a080-4ad9-8fc8-488d0be16a66","owner":[],"postedDate":"January 28th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2026-05-04T14:24:29+00:00","versionOfRecord":[],"versionCreatedAt":"2026-01-28 03:07:10","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8542411","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8542411","identity":"rs-8542411","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}