Ependymoma

Introduction

Ependymoma is a glial tumour that arises from ependymal cells, which line the ventricles and the spinal canal. It may contain cysts and calcification; it is soft and grey-red in appearance. The treatment plan is individualised according to the tumour's location, size and grade.

• Glial cells are supporting cells that help neurons; ependymal cells are associated with the cerebrospinal fluid (CSF) pathways.
• In children the tumour is more often found in the posterior fossa (cerebellum/brainstem), while in adults the spinal cord is the more common location.

Location: Supratentorial / Infratentorial

The tentorium is a thick membrane that separates the brain from the cerebellum. Supratentorial tumours (above it) lie in the cerebral hemispheres and around the lateral/third ventricles; infratentorial tumours (below it) are found in the posterior fossa, around the fourth ventricle, brainstem and cerebellum.

Types & Grading

Pathology grades the tumour according to how closely its cells resemble normal ependymal cells.

• Myxopapillary ependymoma: usually in the lower part of the spinal cord; slow-growing, low grade (I).
• Subependymoma: often in a ventricle; low grade (I).
• Ependymoma: the most common type; most are Grade II. It can occur around the ventricles, in the posterior fossa and in the spinal cord.
• Anaplastic ependymoma: high grade (III); tends to grow faster, often in the posterior fossa.

Grade I tumours usually do not recur when completely removed; in Grade II–III cases additional treatment may be needed after surgery.

Incidence

• Makes up about 2–3% of all primary brain tumours.
• Among the top three brain/spinal cord tumours of childhood.
• About 30% of paediatric cases occur under the age of 3.
• In adults spinal cord location (~60%) is more common; in children brain location (~90%, mostly posterior fossa) is more common.

Symptoms

• Headache (especially in the morning), nausea and vomiting (signs of raised intracranial pressure/hydrocephalus)
• Restlessness, sleeplessness (in babies, a rapid increase in head circumference)
• Balance/walking problems, double vision, loss of coordination of eye movements
• Epileptic seizures, weakness on one side of the body (in supratentorial cases)
• Lower back and leg pain, numbness/tingling, weakness (in spinal cord tumours; may wake you from sleep)
• Loss of bladder/bowel control or paralysis below the waist (in tumours of the lower spinal cord)

Diagnosis

• MRI and CT are used to assess the location and spread; in urgent situations CT has an advantage.
• A definitive diagnosis is made by pathological examination of the tissue removed at surgery.
• Possibility of spread through the CSF pathways (10–15%): follow-up spinal MRI is recommended to screen the spine and the opposite hemisphere (more often in posterior fossa cases in particular).

Treatment

1) Surgery

• The first and most effective approach: maximal safe resection. In Grade I and some Grade II cases, complete removal alone may be curative.
• Microsurgery, neuronavigation and intraoperative neuromonitoring are used with the aim of safe removal.
• If hydrocephalus is present, external drainage during surgery or, if needed, a permanent shunt may be used.
• After surgery, early MRI/CT is used to check the extent of resection.

2) Radiotherapy

• In older children and adults it is often recommended even after complete removal (this is debated); it is strongly indicated if residual tumour remains.
• Craniospinal irradiation: in cases where spread has been detected.
• Focused treatment with conformal/stereotactic techniques (for recurrence or small foci).
• In young children it is postponed where possible because it may adversely affect growth; if needed, chemotherapy is used to gain time.

3) Chemotherapy

• Clear evidence of benefit in newly diagnosed cases is limited. It is mostly considered to postpone radiotherapy or at recurrence.
• Follow-up: clinical neurological assessment and brain/spinal MRI check-ups depending on the location.