Craniopharyngioma

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at July 27, 2016
StartDiseasesCraniopharyngioma

A craniopharyngioma is a very rare type of brain tumor that occurs in every two out of 100,000 people. Though this is typically a benign tumor rather than a malignant tumor, it can still cause problems due to its position in the brain. Only about 220 people are diagnosed with craniopharyngioma each year in the United States. The area where a craniopharyngioma occurs is called the Rathke's pouch, so these tumors are sometimes called Rathke's pouch tumors.

Contents

Definition & Facts

A craniopharyngioma is a specific type of benign brain tumor that develops in embryonic tissue in the pituitary stalk. Because they come from embryonic cells of tooth-forming epithelium, craniopharyngioma are often composed of calcium deposits. Though craniopharyngioma are most common among children between the ages of 9 and 14, they can also happen to men and women in their 50s or 60s.

They are technically classified as benign because they are not made up of cancerous cells. Instead, a craniopharyngioma tends to be a cyst or a calcified clump of cells. The area near the pituitary stalk contains the optic nerve and pituitary gland, so many important bodily functions may be affected by a craniopharyngioma.

Symptoms & Complaints

Due to its location, craniopharyngioma tumors are not normally visible to the naked eye, even if they are rather large. As a craniopharyngioma grows, it tends to put pressure on the brain. This can cause a variety of symptoms that will depend on the size and precise location of the tumor.

Since all craniopharyngioma are by the pituitary gland, which regulates growth and metabolism, many symptoms of a craniopharyngioma in children include unusual growth habits. Patients with a craniopharyngioma may be either underweight or overweight, and if they have had the tumor since childhood, they may be unusually short for their size.

It is also quite common for the craniopharyngioma to put pressure on the optic nerve, causing poor vision or vision loss. Other general symptoms that may be caused by a craniopharyngioma include nausea, headaches, fever, exhaustion, dry skin, thirst, and frequent urination. Occasionally, if the tumor is very large and has been present for a very long time, a person may have developmental delays that result in intellectual disability or physical disability.

Causes

Currently, little is known about what makes a person develop a craniopharyngioma. For unknown reasons, people between the ages of 9 and 14 are most likely to get this type of tumor. A person's risk of getting a craniopharyngioma does not seem to be affected by their gender. African American patients are slightly more likely to get a craniopharyngioma than other demographics.

Since family members of people with a craniopharyngioma are not more likely to get a craniopharyngioma, this type of tumor does not seem to be caused by genetic factors. Since they can start forming again after being removed, it seems likely that a craniopharyngioma may be caused by a physical change in the body. However, there is little research into the subject currently.

Diagnosis & Tests

Since the symptoms of craniopharyngioma can be mild, it may take a long time to arrive at a diagnosis for the condition, and other conditions that cause similar symptoms need to be ruled out first. After conducting a thorough physical examination and asking the patient for a medical history, a doctor may begin to suspect that they have a craniopharyngioma.

The diagnosis can then be confirmed through a few different types of tests. Pituitary function testing can be performed after blood is drawn from the patient. These tests examine the hormone levels in the blood to see whether or not the pituitary is working correctly. A malfunctioning pituitary gland is often caused by a craniopharyngioma.

If the craniopharyngioma has calcium deposits, it will show up on a simple X-ray. However, if it is just a cyst filled with fluid, more detailed imaging test may be required. An MRI scan or a CT scan can be used to detect a craniopharyngioma by taking detailed images of the brain and neck. These scans are also very useful because they show the precise location of the tumor, so doctors know which areas of the brain are being affected by the craniopharyngioma. 

Treatment & Therapy

Even though most types of craniopharyngioma are benign, they should still be removed before they damage the brain further. Craniopharyngioma removal also helps to prevent the tumor from becoming malignant, which tends to happen several years after the craniopharyngioma initially formed. The preferred method of treatment if possible is surgical removal of the craniopharyngioma.

In some occasions, a minimally invasive endoscopic endonasal surgery can be used. This type of surgery allows surgeons to access the affected area through the nasal cavity. However, some cases require doctors to perform an open craniotomy which means that they will need to cut open the scalp to reach the craniopharyngioma.

After surgery, a patient may need radiation therapy to completely eradicate the tumor. Sometimes, the position or size of the craniopharyngioma makes surgical removal unwise. In these cases, a combination of radiation and chemotherapy can help to treat a malignant craniopharyngioma.

Years of pressure on the pituitary gland can leave it unable to function properly, and after surgical removal, massive weight gain is common (hypothalamic disease). Therefore, patients may need hormone replacement therapy or other care from an endocrinologist to adjust their growth hormone levels.

Prevention & Prophylaxis

Since so little is known about the initial cause of a craniopharyngioma, there is not a definitive way to prevent this type of tumor from happening. Malignant craniopharyngiomas usually take quite a while to develop, so prompt removal can help to prevent their occurrence.

Since craniopharyngioma do tend to recur in the same location, doctors recommend that a patient who has been treated for a craniopharyngioma previously continue to get regular checkups. This can help to prevent the craniopharyngioma from growing unchecked if a new one develops again in the future.