title: Intradural Extramedullary Primary Ependymoma of the Craniocervical Junction Combined with C1 Partial Agenesis: Case Report and Review of the Literature.
abstract: BACKGROUND
  Intramedullary ependymomas represent 40%-60% of spinal cord tumors in adults and can be located along the entire spinal cord. Intradural extramedullary (IDEM) ependymomas are very rare with the exception of tumors located at the filum terminale or conus medullaris, with histologic features of myxopapillary ependymomas (World Health Organization grade I).
  
  
  METHODS
  We present the case of a 42-year-old woman with an IDEM ependymoma of the craniocervical junction who experienced neck pain for 5 months. Magnetic resonance imaging of the cervical spine and craniocervical junction showed a large IDEM solid-cystic lesion with anterolateral junction spinal cord compression. A preoperative computed tomography scan did not show any calcified lesion, although a partial agenesis of the C1 posterior arch was observed. During surgery, a well-encapsulated IDEM tumor without dural attachment or medullary infiltration was found, and a total en bloc excision was performed. Histologic examination revealed a grade II ependymoma. The patient had an excellent clinical recovery, with no recurrence after 2 years of follow-up.
  
  
  CONCLUSIONS
  To the best of our knowledge, no other cases of craniocervical junction ependymomas with vertebral bone abnormalities are described in the literature. This association supports the hypothesis that these lesions may originate from the extrusion of ependymal cells before neural tube closure. Differential diagnosis should include other extramedullary tumors that are more frequent in this region, such as meningioma, schwannoma, or dermoid tumor.
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy. Electronic address: cmorselli822@gmail.com.
authors.forename: Carlotta
authors.initials: C
authors.lastname: Morselli
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Andrea G
authors.initials: AG
authors.lastname: Ruggeri
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Pichierri
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Marotta
authors.affiliation: Department of Radiology, Sapienza University of Rome, Rome, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Anzidei
authors.affiliation: Division of Neurosurgery, Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Delfini
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000002:abnormalities*; D004806:Ependymoma / Q000473:pathology / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D019547:Neck Pain / Q000209:etiology; D013117:Spinal Cord Compression / Q000209:etiology; D013120:Spinal Cord Neoplasms / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
keywords: Congenital anomalies; Craniocervical junction; Ependymoma; Intradural extramedullary tumor