There are several other types of brain tumours children can develop. Diagnosis, treatment and outcomes will vary depending on the type of tumour and its location.
Primitive Neuroectodermal Tumours (PNETs)
One out of every five brain tumours in children is a primitive neuroectodermal tumour (PNET). These are fast-growing tumours. They may often spread through cerebrospinal fluid (CSF). They are often found at the back of the brain, in the cerebellum.
Types of PNETs
Medulloblastomas
A medulloblastoma is a type of primitive neuroectodermal tumour (PNET) that is found at the back of the brain, in the cerebellum. This is the most common cancerous brain tumour in children. It is usually diagnosed in children aged four to eight years, and is more common in boys. Different types of medulloblastomas, such as desmoplastic, large cell, anaplastic, behave differently.
For more information see the About Medulloblastomas section of this site.
Supratentorial PNETs
These tumours grow in the upper part of the brain, in the cerebrum and are cancerous (malignant). They are generally more aggressive than medulloblastomas. They are treated with surgery, radiation, chemotherapy. When it grows in the pineal region, this type of tumour is called a pineoblastoma.
High grade glioma
High grade means that the glioma is growing quickly and will often invade healthy tissue. It is considered cancer (malignant). These tumours are rare in children. Examples of high grade gliomas are anaplastic astrocytomas (grade 3) and glioblastoma multiforme (grade 4). They are usually treated by surgery, followed by radiation therapy and chemotherapy
Germ cell tumours
This type of tumour occurs mostly in the area above the pituitary gland (suprasellar region) or in the pineal region of the brain. There are two main types of germ cell tumours: germinomas and non-germinomatous germ cell tumours (also known as secreting germ cell tumours). The most common type is the germinoma. During normal development of a baby, a germ cell develops into an egg cell (in a girl) or a sperm cell (in a boy). In rare cases, these cells stay in a wrong part of the baby’s body, such as the brain where they can produce a tumour. These tumours may spread to other parts of the brain or spine through cerebrospinal fluid (CSF). Germ cell tumours are also called secreting tumours because they produce substances called tumour markers, such as the protein alpha-fetoprotein or the hormone beta-human chorionic gonadotropin (beta-hCG).
Most germ cell tumours are treated with a combination of surgery, chemotherapy, and radiation.
Choroid plexus tumours
Choroid plexus is a folding in the lining of the surface of the ventricles, the hollow channels in the brain. The choroid plexus produces fluid that fills these hollow channels. These tumours occur most often in children under the age of 2. There are two types of tumours in the choroid plexus. Choroid plexus papilloma is a benign tumour that can block the flow of cerebrospinal fluid (CSF). This causes hydrocephalus and increased intracranial pressure. It is treated with surgery, although some children may also need a shunt. Choroid plexus carcinoma is a malignant tumour. It can spread into nearby tissues and into the CSF. Surgery is critical in the treatment of choroid plexus carcinomas. If the tumour cannot be completely removed during the first operation, chemotherapy is used to help complete the removal of the tumour.
Meningioma
This is a rare, benign tumour in children but is more common in adults. It usually grows inside the skull but outside the brain, in the meninges. A person with neurofibromatosis 2 has a higher risk of developing a meningioma. It may be removed by surgery. Radiation may be used if the tumour was not completely removed, or it is growing fast.
Pituitary adenoma
This is a rare, benign tumour in the pituitary gland, which is located in the centre of the brain. This important gland releases chemical messengers called hormones. These hormones control other glands in the body. The pituitary also releases hormones that control growth and water balance. They are diagnosed by the level of hormones in the blood. There are 2 groups of pituitary adenomas.
Types of pituitary adenomas
Space-occupying tumour
These tumours are also called non-secreting tumours. They can prevent the pituitary gland from releasing important hormones. These tumours are usually treated with surgery, and sometimes radiation therapy.
Hormone-secreting tumour
Most pituitary adenomas are hormone-secreting. They release hormones in much greater amounts than is normal. These extra hormones can create problems. The treatment is often based on anti-hormone medications. Examples of this type of tumour are:
- Prolactin secreting adenoma: This tumour releases too much of a hormone called prolactin in the body. This can cause a lack of menstrual periods, infertility, and the release of milk in females. In males, they can cause impotence and the release of milk.
- Growth hormone secreting adenoma: This tumour can cause gigantism because it releases too much growth hormone in the body. This results in rapid growth, joint and muscle soreness, problems with exercising, and fatigue. It may also cause other problems such as diabetes mellitus, kidney problems, and high blood pressure.
- Adrenocorticotropic hormone (ACTH) secreting adenoma: This tumour produces too much of the hormone ACTH. The ACTH causes the adrenal gland to produce too much cortisol, which is another hormone. Cortisol affects the body’s ability to respond well to injury and infection. It may also result in a change in the way fat is distributed in the body (Cushingoid appearance).
Dysembryoplastic neuroepithelial tumour (DNET)
This is a benign tumour that is usually located in outer part of the upper brain, the supratentorial area. One common symptom is seizures. It is treated with surgery.
Schwannoma
This is a benign, slow-growing tumour in the peripheral nerves. People who have neurofibromatosis-2 have a higher risk of developing this tumour.
Rhabdoid tumours
This is a rare, fast-growing cancer found in the central nervous system (CNS) or kidney. It usually occurs in children younger than two years of age. It is treated with surgery, chemotherapy, and radiation.