Types of craniopharyngioma

There are two main types:

Papillary (finger-like and soft) craniopharyngioma; adamantinomatous (very hard) craniopharyngioma

What are craniopharyngiomas?

Craniopharyngiomas are a rare type of benign (non-cancerous) brain tumour, which are seen most commonly above the pituitary gland. Occasionally they are found within the bony cup called the sella, which contains the pituitary gland. They are thought to grow from remnants of the developmental (embryonic) tissue from which the pituitary gland is derived. Growth of these tumours is unpredictable and they tend to compress, and occasionally invade nearby tissues. 

What causes craniopharyngiomas?

The cause 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 their growth.

What are the signs and symptoms of craniopharyngiomas?

Signs and symptoms usually develop gradually. They occur due to local effects from the enlarging tumour compressing vital structures within the brain such as the nerves to the eyes, brain tissue, other surrounding 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 increases in size, the normal pituitary tissue is compressed and can be damaged leading to progressive loss of production of some, or all, of the pituitary hormones. A number of symptoms can occur depending on which hormones are lost. These include growth failure and delayed sexual development in children. See the articles on hypopituitarism, Addison's disease, childhood-onset growth hormone deficiency, growth hormone deficiency, adult-onset growth hormone deficiency, hypothyroidism and diabetes insipidus for further information.

How common are craniopharyngiomas?

Craniopharyngiomas can present at any age, although they 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. Craniopharyngiomas are a very rare condition, with the overall number 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 of the brain. They may be picked up incidentally while investigating the pituitary gland or the brain. 

When a craniopharyngioma is detected, blood tests are also required to determine whether any of the pituitary hormones have been affected. These tumours may ‘squash’ the pituitary and stop it from working properly. Visual field testing may also be carried out to detect any problems with vision.

The diagnosis of craniopharyngioma is confirmed by examining tissue samples removed during surgery under a 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 surrounding structures. The tumour may be approached through the nose. However, if it is very large, it may be necessary to open the skull and reach it. As craniopharyngiomas can be closely attached to the tissues surrounding them, they are often difficult to remove completely. In cases where the craniopharyngioma is cystic, meaning fluid-filled, 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 of the tumour remaining after surgery. Strategies that require further research to understand their benefit fully include inserting radioactive ‘seeds’ into the cysts; stereotactic radiosurgery; and other types of chemotherapy.

If the patient is deficient in any pituitary hormones as a consequence of the craniopharyngioma itself or its management, treatment to replace those hormones maybe required. Such hormone replacement will be initiated and monitored by an Endocrinologist.

Are there any side-effects to the treatment?

As mentioned above, the pituitary may already be damaged by the craniopharyngioma leading to deficiency of one or more hormones. However, surgery and radiotherapy may cause additional damage with further loss of pituitary hormones. Other risks of surgery include bleeding, leakage of the fluid surrounding the brain through the nose, infection and visual defects. Sometimes, treatment of craniopharyngiomas can cause damage to an important part of the brain that lies immediately above the pituitary gland called the hypothalamus. This can cause problems with weight gain, as the hypothalamus is important in appetite and weight control.

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. Regular monitoring for the development of low levels of pituitary hormones is also required, particularly if radiotherapy has been given. It is important to check on a regular basis, that the amount of hormone replacement is effective for those who have already developed hormone deficiencies.

The sometimes-aggressive behaviour of these tumours, combined with their tendency to recur, even after treatment, can lead to repeated medical contact in some cases. However, it is important to note that they are very rare tumours and with the correct treatment, patients should go on to lead a normal life.

Are there patient support groups for people with craniopharyngiomas?

Pituitary Foundation may be able to provide advice and support to patients and their families dealing with craniopharyngiomas.