Grade II Spinal Cord Ependymomas

Ependymomas of the spinal cord originate from the ependymal walls. They have been classified by the World Health Organization into grades I, II, and III. Grade I tumors include myxopapillary ependymomas and subependymomas. Grade II tumors are just called ependymomas and can be further divided as cellular, papillary, clear cell, or tanycytic. Grade III tumors are called anaplastic ependymomas, tend to occur in the brain, and are rare in the spine.

Grade II spinal cord ependymomas (simply called ependymomas) tend to be located somewhat centrally in the cervical spinal cord in association with large satellite cysts.

MRI is the imaging modality of choice. Ependymomas are isointense to slightly hypointense to the spinal cord on T1-weighted images and may have areas of hyperintensity due to hemorrhage. Satellite cysts are T1-hypointense. T2-weighted images reveal a hyperintense mass with or without intramural cysts. Polar (rostral or caudal) cysts and a syrinx may also be seen in the adjacent spinal cord. Hemorrhage may also be seen, sometimes presenting as a "cap sign" (hemosiderin deposits due to chronic hemorrhage at the rostral or caudal margins). Post-contrast images reveal avid and homogeneous enhancement.

Differential considerations for an intramedullary cyst with one or more enhancing nodules includes:

• Ependymoma: Well-circumscribed mass with hemorrhage. More common in the cervical spine.
• Myxopapillary ependymoma:
• Pilocytic astrocytoma: Most common primary spinal cord neoplasm in children. Can be eccentric with indistinct margins. Hemorrhage is uncommon.
• Hemangioblastoma: Look for a hemangioblastoma in the brain, cysts in the pancreas, and cystic or solid lesions in the kidneys to make the diagnosis of von Hippel-Lindau disease.

References

• Balériaux DL. Spinal cord tumors. Eur Radiol. 1999;9(7):1252-8.
• Armstrong TS, Vera-Bolanos E, Gilbert MR. Clinical course of adult patients with ependymoma: Results of the Adult Ependymoma Outcomes Project. Cancer. 2011 Apr 28.