Spinal ependymoma is the most common intramedullary spinal cord tumor in adults, arising from ependymal cells (glial cells lining the central canal). It accounts for approximately 60% of all spinal cord tumors. The cervical spine is the most commonly affected region (40-65%), followed by the thoracic segment. On MRI, it appears as a centrally located lesion causing symmetric cord expansion, T1 iso-hypointense, T2 hyperintense, with homogeneous and intense enhancement. T2 hypointense rim at the upper and lower margins — 'cap sign' — due to hemosiderin deposition is pathognomonic and results from chronic microhemorrhages. Polar cysts (reactive cysts at the cranial and/or caudal ends of the tumor) frequently accompany. Myxopapillary ependymoma variant occurs at the conus medullaris and filum terminale and is more common in young adults. Complete surgical resection is the most important prognostic determinant — the well-defined nature of ependymomas (cleavage plane) facilitates this. In NF2 (neurofibromatosis type 2) associated cases, multiple spinal ependymomas and intracranial ependymomas may coexist.
Age Range
30-60
Peak Age
45
Gender
Equal
Prevalence
Uncommon
Spinal ependymoma develops from ependymal cells lining the central canal of the spinal cord. These cells normally play a role in cerebrospinal fluid production and circulation. Following neoplastic transformation, the tumor originates from the central canal and symmetrically expands the spinal cord — this central origin forms the basis for imaging differentiation of ependymoma from astrocytoma. The tumor grows slowly and is usually low-to-intermediate grade (WHO grade II-III). Its well-defined nature (pseudocapsule or cleavage plane) results from tumor cells not infiltrating surrounding normal cord tissue — this is surgically critical as it allows complete en-bloc resection. The pathophysiology of cap sign is: tumor vessels are fragile and abnormal, prone to chronic microhemorrhages. Hemoglobin released from red blood cell breakdown is phagocytosed by macrophages and deposited as hemosiderin. Hemosiderin is strongly paramagnetic — iron atoms disrupt local magnetic field homogeneity and shorten T2* relaxation time, creating marked signal loss (hypointensity) on T2-weighted and gradient-echo sequences. This hemosiderin deposition concentrates at the upper and lower tumor margins because gravity and CSF flow dynamics accumulate blood degradation products at these locations. Polar cysts form due to altered CSF flow dynamics from the tumor's obstructive effect and reactive gliosis — they are not part of the tumor parenchyma and do not require surgical resection. The myxopapillary variant develops from ependymal cells of the filum terminale, contains mucinous intercellular matrix, and this high water-content mucin produces very bright T2 signal.
T2 hypointense rim at the upper and lower tumor margins — hemosiderin deposition (chronic microhemorrhages). Pathognomonic for ependymoma.
On T2-weighted sequences, a thin, smooth hypointense rim is observed at the upper (cranial) and lower (caudal) tumor margins — 'cap sign'. This hemosiderin deposition becomes conspicuous by contrasting with the bright T2 signal of the tumor. It becomes more prominent as blooming artifact on gradient-echo (GRE) or susceptibility-weighted imaging (SWI) sequences. Cap sign is seen in approximately 20-33% of ependymomas but has high specificity for spinal ependymoma diagnosis when present.
Report Sentence
Hypointense rim is observed at the cranial and caudal margins of the intramedullary lesion on T2-weighted sequences (cap sign), this finding due to hemosiderin deposition is pathognomonic for spinal ependymoma.
T1-weighted sequences show symmetric cord expansion with a centrally located iso-hypointense mass. Tumor margins are usually well-defined. Intratumoral hemorrhage areas may appear as focal T1 hyperintense foci. Cord expansion is typically 2-4 vertebral segments in length (shorter than astrocytoma).
Report Sentence
A centrally located intramedullary mass causing symmetric expansion of the cervical/thoracic spinal cord at ...-... vertebral levels, iso-hypointense on T1, is observed.
T2-weighted sequences show a hyperintense mass within the spinal cord. Polar cysts (peritumoral reactive cysts) showing CSF-isointense signal at the cranial and/or caudal tumor ends frequently accompany. These cysts are not part of the tumor parenchyma — they are reactive formations due to altered CSF flow dynamics. Intratumoral cystic-necrotic areas may also appear T2 hyperintense. Peritumoral edema and syringomyelia may accompany.
Report Sentence
The intramedullary mass shows hyperintense signal on T2 with accompanying CSF-isointense polar cysts at the cranial/caudal end.
On gadolinium-enhanced T1-weighted sequences, ependymoma shows homogeneous and intense enhancement. The enhancement pattern is smooth and symmetric, clearly defining tumor margins. Polar cysts do not enhance (non-neoplastic). Intratumoral cystic/necrotic areas may not enhance. Contrast-enhanced sequences are critical for tumor size, differentiation from peritumoral edema, and surgical planning.
Report Sentence
The intramedullary mass shows homogeneous and intense enhancement on contrast-enhanced sequences, this pattern is consistent with well-differentiated intramedullary tumor (ependymoma).
CT may show spinal canal widening and posterior vertebral body scalloping (erosion). These findings suggest chronic, slow-growing intramedullary mass. Calcification is rarely seen. CT myelography (intrathecal contrast) demonstrates the intramedullary location of the tumor but MRI is currently preferred.
Report Sentence
Spinal canal widening and posterior vertebral body scalloping at ...-... vertebral levels is observed, consistent with chronic intramedullary mass.
Criteria
Most common type. Cervical-thoracic cord. Well-defined, homogeneous enhancement, cap sign.
Distinct Features
Central location, symmetric expansion, low recurrence rate after complete resection
Criteria
Conus medullaris/filum terminale location. Young adults (20-40 years). Very bright T2 (mucinous matrix).
Distinct Features
Best prognosis, slow growth, drop metastasis rare, very bright T2 due to mucinous stroma
Criteria
High-grade malignant form. Heterogeneous enhancement. More aggressive growth, risk of CSF dissemination.
Distinct Features
Poor prognosis, heterogeneous MR appearance, necrosis and hemorrhage more frequent, leptomeningeal spread risk
Criteria
Multiple spinal ependymomas in neurofibromatosis type 2. Intracranial ependymoma may accompany.
Distinct Features
Bilateral vestibular schwannoma, meningiomas, and ependymomas together (NF2 triad)
Distinguishing Feature
Astrocytoma shows eccentric cord expansion, indistinct margins, heterogeneous/variable enhancement; ependymoma is central, symmetric, well-defined, homogeneous enhancement with cap sign
Distinguishing Feature
Vertebral hemangioma is located in the vertebral body (not intramedullary), T1 and T2 hyperintense (fat), differentiated by polka-dot CT pattern
Distinguishing Feature
Epidural abscess is extramedullary, shows rim enhancement, marked DWI restriction, accompanied by clinical infection signs
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
6-monthSpinal ependymoma is treated with complete surgical resection (en-bloc). The well-defined cleavage plane enables complete resection, which is prognostically critical. Five-year survival after complete resection is 80-90%. Adjuvant radiotherapy is recommended for subtotal resection. Myxopapillary variant has the best prognosis. Adjuvant therapy is mandatory for anaplastic ependymoma (grade III). NF2 screening is recommended for multiple ependymomas.
Spinal ependymoma is treated with surgical resection. The well-defined nature of ependymomas (cleavage plane) allows complete resection, which is prognostically critical. Five-year survival after complete resection is 80-90%. Adjuvant radiotherapy is recommended for subtotal resection. Myxopapillary variant has better prognosis. Multiple ependymomas may occur in NF2-associated cases.