Ependymoma

An ependymoma is a tumour that arises from the ependyma, a tissue of the central nervous system (CNS). In children, these tumours are typically found intracranially, whereas in adults, they are more often located in the spinal cord. The fourth ventricle is the most common site for intracranial ependymomas.

On rare occasions, ependymomas can also appear in the pelvic cavity. Syringomyelia, a condition characterised by the development of a cyst within the spinal cord, can be caused by an ependymoma. Additionally, ependymomas are associated with neurofibromatosis type II.

Signs and Symptoms

Patients with ependymomas may present with a variety of signs and symptoms, including:

• Severe headache
• Visual loss due to papilledema
• Vomiting
• Bilateral Babinski sign
• Drowsiness following the onset of other symptoms
• Gait changes, such as rotation of the feet when walking
• Impaction or constipation
• Reduced back flexibility

Morphology

Ependymomas are characterised by cells with regular, round to oval nuclei within a variably dense fibrillary background. Tumour cells may form gland-like structures that resemble the embryologic ependymal canal, often featuring long, delicate processes extending into the lumen. More frequently, perivascular pseudorosettes are observed, where tumour cells are arranged around blood vessels with intervening zones of thin ependymal processes directed toward the vessel wall.

It has been suggested that ependymomas originate from radial glia rather than ependymal cells, as their name would imply.

Diagnosis

Ependymomas account for approximately 5% of adult intracranial gliomas and up to 10% of CNS tumours in children. Their incidence peaks at around 5 years of age and again at 35 years. These tumours usually develop from cells lining the brain's cavities and the spinal cord canal, often originating from the floor of the fourth ventricle. Symptoms may include headache, nausea, and vomiting due to cerebrospinal fluid obstruction, potentially causing hydrocephalus. Spinal ependymomas can also arise in the conus medullaris and supratentorial locations. Other symptoms might include loss of appetite, difficulty sleeping, temporary inability to distinguish colours, uncontrollable twitching, seeing vertical or horizontal lines in bright light, and temporary memory loss.

Myxopapillary ependymoma (MPE), a benign subtype, is localised and slow-growing, primarily occurring in the lumbosacral region of young patients. MPEs constitute about 90% of tumours in this region.

Treatment

The initial treatment strategy for ependymomas involves maximum surgical resection followed by radiation therapy. Chemotherapy is generally limited to specific cases, such as in young children or when the tumour persists after resection. The use of prophylactic craniospinal irradiation is controversial due to its variable efficacy and the fact that most recurrences occur at the resection site. If cerebrospinal infiltration is confirmed, more extensive radiation fields may be required.

Malignant varieties of ependymomas, including anaplastic ependymomas and ependymoblastomas, are treated similarly to medulloblastomas but have a less favourable prognosis. These may require a combination of radiation therapy and chemotherapy. Ependymoblastomas, primarily affecting infants and young children, may spread through cerebrospinal fluid and usually necessitate radiation therapy.

Extraspinal ependymoma (EEP), also known as extradural ependymoma, may be mistaken for a sacrococcygeal teratoma.

Prognosis

The five-year survival rate for ependymoma patients stands at 83.9%. However, the prognosis for recurrence is poor, often necessitating palliative care to manage symptoms.

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Self-assessment MCQs (single best answer)

What is the most common site for intracranial ependymomas in children?

Which condition can be caused by an ependymoma?

Ependymomas are associated with which genetic disorder?

What histological feature is commonly seen in ependymomas?

Myxopapillary ependymoma primarily occurs in which region?

What is the primary treatment strategy for ependymomas?

Which symptom is NOT commonly associated with ependymomas?

What is the five-year survival rate for ependymoma patients?

Which subtype of ependymoma is primarily treated similarly to medulloblastomas?

Which of the following is a potential consequence of cerebrospinal fluid obstruction caused by ependymomas?