Alternative names for craniopharyngioma
Papillary craniopharyngioma; adamantinomatous craniopharyngioma.
What are craniopharyngiomas?
Craniopharyngiomas are a rare type of benign brain tumour, which most commonly occur above the pituitary gland, but occasionally are found within the bony box (sella) containing the pituitary gland. Craniopharyngiomas are thought to be derived from remnants of the developmental (embryonic) tissue from which the pituitary gland is derived. Growth of these tumours is unpredictable and they have a tendency to compress neighbouring tissues and occasionally to invade nearby tissues.
What causes craniopharyngiomas?
The cause of craniopharyngiomas is unknown. It is unclear why embryonic remnants persist in some people and whether these always slowly enlarge or whether some trigger factor is needed to start them growing.
What are the signs and symptoms of craniopharyngiomas?
Signs and symptoms of craniopharyngiomas usually develop gradually. Symptoms relate to local effects from the enlarging tumour compressing vital structures within the brain such as the visual pathways, brain tissue, major blood vessels, nerves and the pituitary gland. Symptoms depend on the size and location of the tumour and may include headaches, loss of vision, double vision, unsteadiness, nausea and vomiting. In addition, as the tumour enlarges, the normal pituitary tissue is compressed and can be damaged, leading to progressive loss of production of some or all of the pituitary hormones (hypopituitarism). A number of symptoms can occur depending on which hormones are lost. See the article on hypopituitarism for further information.
How common are craniopharyngiomas?
Craniopharyngiomas can present at any age, although are most common at two age ranges: between age five and 14 years (they account for about 4 in 100 of all childhood tumours between birth and 14 years of age), and between age 50 and 74 years. It is a very rare condition, with the overall incidence reported to be about 0.5 to 2.0 new cases per 100,000 people every year. Men and women are affected equally and there are no reported racial differences.
Are craniopharyngiomas inherited?
Craniopharyngiomas are not inherited.
How are craniopharyngiomas diagnosed?
Craniopharyngiomas are diagnosed using computerised tomography (CT) or magnetic resonance imaging (MRI) scans of the pituitary area. They may be picked up incidentally while investigating the pituitary gland or the brain.
Blood tests are also required to determine if there are any pituitary hormone deficiencies. Visual field testing may also be carried out to detect any visual abnormality. These investigations are all performed as outpatient appointments.
The diagnosis is confirmed through examining tissue samples removed during surgery under the microscope.
How are craniopharyngiomas treated?
In most cases, surgery is the treatment of choice to try and remove as much of the tumour as possible without damage to adjacent structures. The tumour may be approached through the nose (transsphenoidally), but if it is very large, it may be necessary to open the skull (craniotomy). As craniopharyngiomas can be closely attached to the tissues surrounding them, they are often difficult to remove completely. In cases where the craniopharyngioma has a lot of cysts (fluid filled areas), the fluid can be drained during surgery to reduce the size of the tumour and hence reduce the pressure on surrounding tissues.
Radiotherapy may also be offered to prevent further growth of any tumour remaining after surgery. Strategies that require further research to understand their benefit fully include inserting radioactive ‘seeds’ or bleomycin (chemotherapy) into the cysts; stereotactic radiosurgery; and other types of chemotherapy.
If the patient is deficient in one or more hormones, treatment to replace those hormones will be required. See the article on hypopituitarism for further information.
Are there any side-effects to the treatment?
As mentioned above, the pituitary may already have been damaged by the craniopharyngioma leading to deficiency of one or more hormones, but surgery and radiotherapy may cause additional damage with further hormonal loss. Other risks of surgery include bleeding, leakage of the fluid surrounding the brain through the nose, infection, visual defects and problems with water and salt balance.
What are the longer-term implications of craniopharyngiomas?
Patients will need follow-up appointments for life with regular MRI scans to check for any tumour recurrence. Follow-up is also required to check if any hormone deficiencies have developed and this especially needs to be repeated if radiotherapy has been given. It is important to check, on a regular basis, that hormone replacement is being effective for those who have already developed hormone deficiencies.
The sometimes aggressive behaviour of these tumours, combined with their tendency to recur, even following treatment, can lead to repeated medical contact in some cases. However, it is important to note that craniopharyngiomas are very rare and with the correct treatment, most patients lead a normal life.
Article added: April 2012. Review due: April 2014.