Myxopapillary ependymoma of the filum terminale

Imaging of spine neoplasm

Although most often back pain is of benign origin, it can occasionally be a harbinger of a more serious spinal condition, including spine neoplasm. Knowledge of the typical clinical history of spinal tumors and an understanding of the innervation of the spine and surrounding supporting structures may allow us to better understand when to pursue advanced imaging in the evaluation of spinal pain syndromes. Many radiologists have divided the differential diagnosis of neoplasms of the spine into compartments. These compartments include the extradural compartment, intradural/extramedullary compartment, and the intramedullary compartment.

Intradural extramedullary Ewing tumor of the lumbar spine

A 38-year-old man presented with a highly symptomatic lumbar intradural extramedullary tumor. MRI features strongly suggested a myxopapillary ependymoma, with a possible drop metastasis. No filum terminale or spinal-cord attachment to the tumor was seen intraoperatively. Histopathology, surprisingly, indicated a malignant round-cell tumor, strongly CD 99-positive, and FISH indicated a rearranged ESWR1 locus. A diagnosis of Ewing tumor (ET) was made. Only eight cases in the lumbar region have been previously reported.

Intraparenchymal myxopapillary ependymoma: case report

OBJECTIVE AND IMPORTANCE

Myxopapillary ependymoma is a histological variant of ependymoma found in the cauda equina region. The most characteristic histological feature of myxopapillary tumors is the abundance of intercellular and perivascular mucin and the arborizing vasculature, which tends to form papillae. Primary intracerebral myxopapillary ependymomas are extremely rare; only three cases have been reported in the previous literature.

CLINICAL PRESENTATION

A 68-year-old man presented with disorientation and dizziness caused by a cystic left frontal intraparenchymal lesion. This proved to be a myxopapillary ependymoma. Similarities to previously reported cases are discussed, as are the findings on magnetic resonance imaging. There is also a literature review of the histological findings, natural history, and outcome of surgically treated myxopapillary ependymoma.

INTERVENTION

The lesion was totally removed. After surgery, the patient was neurologically intact and had an uneventful recovery.

CONCLUSION

This is the fourth reported case of histologically proven primary myxopapillary intracranial ependymoma.

Myxopapillary ependymoma of the ischioanal fossa

Ependymomas outside the confines of the cranium and spinal cord are rare. Direct extension into the soft tissues of the sacrococcygeal area may occur from a primary ependymoma of the spinal cord, cauda equina or filum terminale. Alternatively they may occur as a primary pre-sacral, pelvic and abdominal tumour, or as a primary tumour of the skin and subcutaneous tissue of the sacrococcygeal area without any demonstrable connection with the spinal cord. The Authors report a case of myxopapillary ependymoma of the ischioanal fossa, demonstrated by MRI. To our knowledge, our case is the first lesion reported at this site.

Intraosseous sacral myxopapillary ependymoma and the differential diagnosis of sacral tumors

Although involvement of other regions of the spinal cord and brain stem is seen, myxopapillary ependymoma is most commonly found at the filum terminale or cauda equina. Less commonly, myxopapillary ependymoma may occur outside the central nervous system from direct metastatic extension of an intrathecal tumor, and rarely it may present as a primary tumor outside the thecal sac. The authors present a case of primary sacral myxopapillary ependymoma, which was first diagnosed as a chordoma. They then discuss the magnetic resonance imaging findings of this and other sacral tumors. Myxopapillary ependymoma should be considered in the differential diagnosis for a primary expansile sacral mass along with other lesions such as chordoma, aneurysmal bone cyst, and giant cell tumor.