What is a craniopharyngioma?
During pregnancy, a duct forms in the embryo’s pituitary gland, which later closes again. In some babies, however, cell remnants remain and begin to grow uncontrollably. This results in a craniopharyngioma (from the Greek word kranion = skull and pharynx = pharynx ). This brain tumor in the pituitary gland is filled with fluid and surrounded by a solid capsule.
The craniopharyngioma does not grow into the neighboring brain tissue or form metastases (secondary tumors). However, due to its increasing size, it displaces the neighboring tissue. As a result, the tumor can press on the optic nerves, the hypothalamus or the pituitary gland, causing headaches, dizziness, hormonal disorders and concentration problems. Due to the non-specific symptoms, craniopharyngioma is difficult to diagnose. However, the earlier the tumor is treated, the fewer the long-term consequences. Experts distinguish between adamantinomatous craniopharyngioma in children and adolescents, which is often interspersed with calcification, and papillary craniopharyngioma in adults.
Frequency and age
In most cases, a craniopharyngioma becomes apparent at a young age. 90 percent of all craniopharyngiomas occur in children and adolescents. One in two of these brain tumors develop between the ages of five and ten. Boys and girls are represented in roughly equal numbers. In adults, a craniopharyngioma is usually diagnosed between the ages of 50 and 75. In total, one to two in a million people are newly diagnosed with this disease every year.
Craniopharyngioma: causes and risk factors
Why the cells left over from embryonic development start to proliferate in some people is still unclear. The craniopharyngeoma forms from cells of a connecting duct between the brain and the throat, the craniopharyngeal duct, which normally disappears on its own by birth.
Symptoms: Visual disturbances typical of craniopharyngiomas
When the cells of the craniopharyngioma begin to proliferate, those affected do not notice it at first. This is because they usually grow very slowly. Complaints only arise when neighboring structures are being squeezed by the tumor. Typical symptoms of a craniopharyngioma are
- Visual disturbances
- Headache
- Nausea and vomiting
- Hormone disorders
- Growth disorders/developmental delay
- Increased thirst
- Increased urine excretion
- Obesity
- listlessness/fatigue
On the one hand, the brain tumor often presses on the third ventricle of the brain. As a result, the cerebrospinal fluid can no longer circulate unhindered and the intracranial pressure increases. This leads to a feeling of pressure in the head and vomiting, especially in the morning on an empty stomach. The tissue around the tumor is also irritated by the tumor.
As the optic nerves run directly past the pituitary gland, the tumor often causes visual disturbances, such as visual field defects. Those affected then no longer see some things at the edge of their field of vision. In children, it is noticeable that they do not grow in line with their age or that puberty with its characteristics (such as body hair) does not occur. The reason for this is that growth and sex hormones are produced in the pituitary gland. The hormone TSH, which stimulates the thyroid gland, is also produced there. Hypofunction of the thyroid gland and adrenal glands are therefore also signs of a craniopharyngioma.
Craniopharyngioma: Great thirst and excessive appetite
Since the tumor also upsets the body’s water balance, those affected are often noticeably thirsty and therefore excrete an above-average amount of urine. Sometimes they also have an excessive appetite due to the impaired pituitary gland and eat far more than they need. Many of those affected are therefore very overweight. Relatives often also notice a psychological change in the patient. Due to all these connections, craniopharyngioma significantly impairs the quality of life of patients, even if the tumor itself is benign.
Craniopharyngioma: Diagnosis by us
If you tell us about your or your child’s complaints of headaches, visual disturbances, severe thirst and increased urine output or growth retardation, we will order a computer tomography (CT) or magnetic resonance imaging (MRI) of the skull. CT scans allow doctors to recognize the craniopharyngioma with its cysts and calcifications. However, details are often difficult to see on CT due to the many bony structures in the skull. An MRI is usually clearer and can also detect small craniopharyngiomas. CT, on the other hand, shows calcifications better. In some cases we will therefore use both methods.
Additional tests that we arrange concern:
- Hormones
- Weight
- Size
- Water and salt balance
- Visual acuity/visual field
If a craniopharyngioma is suspected, we normally order a measurement of the hormone level in the blood and urine. If certain hormones are out of balance, this allows conclusions to be drawn about the areas in which the tumor has spread. In addition, those affected are measured and weighed in order to compare the data with their age group. In particular, if children and adolescents are too small and too heavy for their age, this can be an indication of a craniopharyngioma. The water and salt balance must also be checked to detect any abnormalities. From all this data, we can then see how large the tumor is and which areas of the brain it is affecting.
Diagnosis by the ophthalmologist
An ophthalmologist should examine the back of the eye with an ophthalmoscopy. You should also determine the visual acuity and measure the visual field to detect possible deficits. If a craniopharyngioma is suspected, visual evoked potentials (VEP) can be used to test whether the visual pathway is damaged: electrodes are attached to the head to measure the brain waves of the visual cortex. The eyes are then specifically irritated by flashes of light or patterns. Due to the brain waves, the doctor can sometimes see better than in the MRI image if the craniopharyngioma is affecting the visual pathway.
Craniopharyngioma: prevention, early detection, prognosis
It is not yet clear why some people develop a craniopharyngioma. That is why you cannot prevent this brain tumor. However, it is generally advisable not to expose children in particular to unnecessary radiation and to protect them from chemicals. A healthy lifestyle with a varied, low-sugar and low-fat diet and plenty of exercise in the fresh air also helps to increase resistance to illness.
If you notice that you or your child can no longer see everything or is excessively thirsty, you should have this checked by a doctor. You should also not ignore frequent headaches associated with a feeling of pressure, but rather have them checked out at an early stage. If you have children, you should attend all check-ups on time. The pediatrician can recognize in good time if a child is not developing according to age and can initiate further examinations in good time if there are any abnormalities.
Long-term impairment despite surgery
The earlier the craniopharyngioma is discovered and treated, the better the chances of recovery. If the tumor can be completely removed during the operation, only one in ten patients has a relapse in the five years that follow. However, if the tumor grows again after the operation, the risk increases despite a second operation. In this case, the risk of not surviving the next five years is up to 20 percent. It is important that an experienced surgeon performs the operation with a good team.
In the long term, however, attention span and memory may be impaired, particularly in children, even if the operation goes well. In many patients, the kidneys also never function fully again. The excessive thirst lasts a lifetime for those affected. The feeling of satiety and impulse control in general also do not function adequately in many of those affected, so that many suffer from eating disorders and obesity with all the other health consequences. Children have to be given growth hormones from outside because the body usually does not produce enough. Anyone who has ever had a craniopharyngioma should attend annual check-ups with oncology specialists for the rest of their life and also have their hormones tested regularly so that they can be replaced with medication if necessary.
Craniopharyngioma: surgery is the best treatment option
A craniopharyngioma usually requires surgery. If the tumor is still relatively small and well encapsulated, it can be completely removed by experienced neurosurgeons without damaging adjacent structures. However, if the tumor has already grown too far into the hypothalamus or the optic nerves, this becomes difficult. Healthy tissue and tumors are often barely distinguishable from each other. There is a high risk that individual tumor cells will remain and begin to proliferate again. A second operation is then necessary. In this case, it is sometimes sufficient to puncture a cyst that has formed again.
If the craniopharyngioma could not be completely removed during the operation or is only punctured, this is usually followed by radiotherapy. This is intended to destroy any remaining tumor cells. Radiation treatment usually takes several weeks. However, many of those affected also have to take long-term medication. Hormone replacement in particular is often necessary because the body does not produce sufficient amounts of thyroid, growth or sex hormones. Accompanying psychotherapy can help those affected to come to terms with the operation and the long-term consequences of the disease.