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Brain and spinal tumours

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Brain and spinal cord cysts

Benign conditions of the brain and spinal cord are non-cancerous. Cysts are sacs that contain fluid or semi-solid material. Cysts found in the brain and spinal cord may contain cerebrospinal fluid, blood, tissue or tumour cells.

Although cysts tend to be non-cancerous, they may be found in parts of the brain and spinal cord that control vital functions. They may also develop inside or beside low-grade or high-grade tumours. Usually only one cyst occurs. However, many tiny cysts may be found inside a high-grade tumour.

There are no known risk factors for cysts of the brain and spinal cord.

The signs and symptoms of a cyst in the brain and spinal cord are the same as those of tumours. The specific symptoms depend on the location of the cyst. They usually appear when the cyst is large enough to affect brain or spinal cord function.

If the signs and symptoms of a brain or spinal cord tumour are present, or if the doctor suspects a tumour, tests will be done to make a diagnosis. These tests will help the doctor determine if a cyst or tumour is present.

The different types of cysts are named for the type of tissue in which they begin or for the material they contain.

Arachnoid cyst

Arachnoid cysts, sometimes called leptomeningeal cysts, start in the subarachnoid space (the space between the arachnoid and pia mater layers of the meningesmeningesThe membranes that cover and protect the brain and spinal cord., which form a membrane-like covering around the brain and spinal cord). Arachnoid cysts occur:

  • in both adults and children
  • more often in males than in females

Treatment

Treatment options for arachnoid cysts may include:

  • active surveillance
    • Small cysts that are not causing symptoms may be watched with periodic scans.
    • Many arachnoid cysts never grow or cause symptoms.
  • surgery
    • Surgery is done if the cyst causes symptoms or is growing.
    • The usual procedure is to open the wall of the cyst and allow it to drain into the normal cerebrospinal fluid (CSF) passageway.
    • If the cyst blocks the flow of CSF through the brain, a shunt may be inserted to help divert the fluid and restore the normal flow.

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Colloid cyst

Colloid cysts develop in the third ventricle. They likely begin to form when the central nervous system develops, while the baby is still in the womb. These cysts may sit quietly until adulthood when they grow large enough to block the flow of CSF, causing hydrocephalus (a buildup of CSF in the brain). A buildup of CSF increases the pressure in the brain, which causes symptoms.

Treatment

The best treatment options for colloid cysts depend on the person’s anatomy and the location of the cyst. Treatment options may include:

  • surgery
    • Surgery may be used to drain or remove a colloid cyst.
      • Removing colloid cysts can be challenging because of their location on or near the third ventricle.
    • Surgery may also be used to place a shunt to drain the CSF and relieve pressure on the brain.
  • active surveillance
    • Small cysts that are not causing symptoms may be watched with periodic scans.

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Dermoid cyst

Dermoid cysts likely develop during the early weeks of a baby’s development in the womb. Symptoms are noticed years after birth.

  • Dermoid cysts form when cells that normally belong to the face and bones move to the brain or spinal cord.
  • Dermoid cysts often contain hair follicles, bits of cartilage or sebaceous glands that produce oils and fat.
  • These cysts are most common in children under 10 years of age.
  • In older children (over the age of 10) and young adults, dermoid cysts most commonly develop in the lower end of the spine.
  • Other common sites include:
    • the cavity of the fourth ventricle of the brain
    • the base of the brain
    • under the surface of the frontal lobe

Treatment

Dermoid cysts are usually removed by surgery. Cysts can regrow if they are not completely removed (including the sac-like lining). The growth may be very slow and it could be years before symptoms return.

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Epidermoid cyst

Epidermoid cysts, also referred to as epidermoid tumours, likely develop during the early weeks of a baby’s development in the womb. They grow very slowly and it may be several decades before symptoms are noticed.

  • The cyst forms when cells meant to be skin, hair or nail tissue move to the brain or spinal cord.
  • Epidermoid cysts often contain remnants of skin cells or tiny pieces of cartilage.
  • Epidermoid cysts occur more often in the brain than in the spinal cord.
  • They are most commonly found in middle-aged adults.
  • These cysts tend develop where the top part of the brain meets the brain stem, near the pituitary gland or along the skull.

Treatment

Epidermoid cysts are usually removed by surgery. Cysts can regrow if they are not completely removed (including the sac-like lining). The growth may be very slow and it could be years before symptoms return.

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Pineal cysts

Cysts in the pineal gland are usually found by accident when the person has an MRI for other reasons. The reason they develop is unclear. It is unusual for pineal cysts to cause signs or symptoms. When they do, it is either because there has been increased CSF production or bleeding into the cyst.

  • Most people with pineal cysts never develop symptoms and the cyst usually doesn’t grow very large.
  • Pineal cysts are rarely associated with underlying tumours. If there is a tumour present, it is easily identified with an MRI scan.

Treatment

Treatment for pineal cysts is active surveillance.

  • Repeat scans may be done over time to make sure the cyst isn’t growing and there is no associated tumour.
  • Once doctors confirm that there is no associated tumour:
    • Periodic scans are done to check if the cyst is growing.
    • Scans may be done if the person develops symptoms.

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Tumour-associated cysts

Both benign and malignant tumours may be associated with cysts. These cysts are sometimes called tumour cysts. An underlying tumour associated with a cyst is usually obvious because a CT or MRI scan shows a nodule or lump next to the cyst.

Treatment

Treatment options for tumour-associated cysts depend on whether the tumour is low grade (benign) or high grade (malignant).

  • Low-grade tumours, including hemangioblastomas, pilocytic astrocytomas and gangliogliomas, are commonly associated with cysts and are usually treated with surgery.
  • High-grade tumours may be associated with cysts and may require radiation with or without chemotherapy in addition to surgery.

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