Your pathology report for myxopapillary ependymoma

by Jason Wasserman MD PhD FRCPC
December 3, 2025

Myxopapillary ependymoma is a type of glial tumor, meaning it develops from glial cells, which are support cells in the brain and spinal cord. It is considered a WHO grade 2 tumor. Although grade 2 tumors grow more slowly than high-grade tumors, myxopapillary ependymomas can still cause symptoms because they grow in tight spaces and may spread through the cerebrospinal fluid (CSF) to other areas of the spine.

This tumor most commonly arises in the conus medullaris and filum terminale, the lower end of the spinal cord. Myxopapillary ependymoma is the most common tumor of this region in both adults and children.

Where does this tumor occur?

Most myxopapillary ependymomas arise in the lower spine, especially:

• The conus medullaris, where the spinal cord tapers.

• The filum terminale, the thin cord at the bottom of the spinal canal.

• The cauda equina, a bundle of nerves resembling a “horse’s tail.”

Less commonly, these tumors can develop in:

• The upper spinal cord.

• The ventricles of the brain.

• The sacrum or soft tissues near the tailbone.

• Rarely, locations outside the nervous system, such as the lung or pelvic region.

When the tumor is found in an unusual location, doctors will first confirm that it did not start in the lower spine and spread upward.

What symptoms does it cause?

Because myxopapillary ependymomas grow in the lower spinal canal, symptoms often relate to pressure on spinal nerves.

Common symptoms include:

• Lower back pain, often long-standing.

• Sciatica, or pain radiating down one or both legs.

• Weakness or numbness in the legs.

• Difficulty walking or problems with balance.

• Bladder or bowel dysfunction, such as incontinence.

• Sexual dysfunction, including impotence in men.

Some patients develop symptoms gradually, while others may experience sudden worsening if the tumor bleeds or expands quickly.

How is this diagnosis made?

Imaging

Diagnosis usually begins with an MRI of the spine, which shows an oval, well-defined, vividly enhancing mass in the lower spinal canal. The tumor often causes widening of the spinal canal, and in children, it may appear larger and more complex. MRI can also identify CSF seeding, meaning small tumor nodules that have spread along the lining of the spinal canal.

Biopsy and microscopic features

The diagnosis is confirmed after surgical removal or biopsy. A pathologist examines the tumor under the microscope. Typical features include:

• Papillary structures, in which tumor cells form finger-like projections around blood vessels.

• Myxoid (“mucoid”) material is a jelly-like substance that accumulates around vessels and in small cysts.

• Spindle-shaped or epithelioid tumor cells are arranged radially around these structures.

• Low mitotic activity, meaning very few dividing cells.

• Occasional giant tumor cells or eosinophilic spherules.

A more aggressive form, called anaplastic myxopapillary ependymoma, is rare and shows higher cell density, increased mitoses, necrosis, or microvascular proliferation.

Immunohistochemistry

Immunohistochemistry (IHC) uses dyes attached to antibodies to highlight specific proteins in tumor cells.

In myxopapillary ependymoma:

• GFAP (a glial marker) is strongly positive, confirming glial origin.

• S100 and CD56 are often positive.

• EMA (epithelial membrane antigen) may be negative or only faint (“dot-like”), helping distinguish it from other spinal tumors.

• OLIG2 is usually negative, helping separate it from astrocytomas.

• Some tumors may stain with specific cytokeratin markers, but this does not mean they are carcinomas.

These patterns help differentiate myxopapillary ependymoma from tumors that can mimic it, such as schwannoma, chordoma, or metastatic cancer.

Molecular tests

Most myxopapillary ependymomas are diagnosed based on their microscopic appearance and location. Molecular testing may include:

• DNA methylation profiling, which examines chemical patterns on DNA and can help confirm the diagnosis, especially in unusual cases.

• Copy-number analysis, which may show gains of chromosome 16 or losses of chromosome 10, although these findings are not specific.

No single genetic mutation has been identified as the cause of these tumors.

WHO grade

The World Health Organization classifies myxopapillary ependymoma as WHO grade 2.

WHO grade 2 means:

• The tumor grows more slowly than high-grade cancers.

• It may recur after surgery, especially if removal is incomplete.

• It can spread along the spinal canal through the CSF.

• It rarely spreads outside the central nervous system.

Although grade 2 tumors are not considered malignant in the same way as grade 3 or 4 tumors, they require careful follow-up and sometimes additional treatment because they tend to recur or spread within the spine.

Prognosis

Most children and adults with myxopapillary ependymoma have an excellent long-term outlook, with 10-year survival rates over 90%. However, many patients require ongoing treatment because the tumor tends to recur—especially when complete removal is not possible. Tumors in the conus medullaris may adhere tightly to the spinal cord, making complete resection more difficult and recurrence more likely.

Spinal tumors in children are more likely to show CSF dissemination, meaning small tumor implants appear elsewhere in the spinal canal. In some pediatric series, this is seen at diagnosis in up to half of patients. Because of this, children often need imaging of the entire spine and sometimes the brain at diagnosis and during follow-up.

Radiation therapy can improve progression-free survival, especially when residual tumor remains after surgery. Cytologic atypia (unusual-looking tumor cells) does not appear to worsen prognosis, but tumors with anaplastic features behave more aggressively.

Tumors arising in the sacrum or coccyx, rather than inside the spinal canal, have a higher risk of spreading outside the nervous system.

What happens after the diagnosis?

Your care team will discuss treatment options based on the tumor’s size, location, and whether it has spread. Surgery is the primary treatment and may be curative if the tumor can be removed completely. If some tumor remains, or if there is CSF spread, radiation therapy may be recommended.

Because recurrence can occur years later, even after successful treatment, regular follow-up with MRI scans is essential. Many patients live full, active lives with appropriate treatment and monitoring.

Questions to ask your doctor

• Was the tumor completely removed during surgery?

• Do I need imaging of my entire spine or CSF testing?

• Are there signs that the tumor has spread within the spinal canal?

• Do you recommend radiation therapy after surgery?

• How often will I need follow-up MRIs?

• If the tumor comes back, what are the treatment options?

• Is this tumor likely related to a genetic condition in my family?