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Myxopapillary ependymomas are slow-growing tumors which manifest almost solely in the conus-cauda-filum terminale region of young adults. These tumors are histologically characterized by neoplastic cells arranged in a papillar manner around vascularized mucoid stromal cores. Myxopapillary ependymoma corresponds to WHO Grade I glioma.
The average age at presentation is 36.4 years, with a male predominance (2.2:1). Myxopapillary ependymomas are the most common intramedullary neoplasm found at the conus/cauda equina segment. These lesions have been reported to occur in the cervical and thoracic spinal cord, in the brain parenchyma, and within the lateral ventricles.
Myxopapillary ependymomas are typically associated with a long history of back pain.
MRI demonstrates a sharply circumscribed lesion with often very bright enhancement. Cystic changes and intra-tumoral hemorrhage may be present.
Myxopapillary ependymomas are characterized by GFAP-expressing, cuboidal to elongated tumor cells radially arranged in a papillary manner around vascularized stromal cores. Mitotic activity is very low. A mucoid matric material accumulated between tumor cells and blood vessels, and fills the tumor microcysts.
Myxopapillary ependymomas are encapsulated, lobulated tumors, soft and grayish in appearance.
The molecular genetics of myxopapillary ependymomas have yet to be characterized.
Disease-free survival depends fully on extend of resection at initial presentation. It is imperative that the tumor capsule not be violated during resection. Intra-operative diagnosis should be made based on tumor appearance, with the consequent goal of gross total resection without violation of the tumor capsule. Biopsy for frozen section should not be performed to avoid the risk of spillage of tumor cells into the thecal sac.