Craniopharyngioma
What is Craniopharyngioma?
Craniopharyngiomas are rare tumors that develop in the brain. They are most often diagnosed in children ages 5-14 years. These tumors account for about 6% of childhood brain tumors. There are 100-200 cases of pediatric craniopharyngiomas in the United States each year. The 10-year survival rate for craniopharyngioma is 80-90%.
Craniopharyngiomas are usually made up of a solid mass and fluid-filled cyst. They are benign, slow growing tumors and rarely spread to other parts of the brain. However, the tumor can be very harmful due to the effect on important surrounding brain structures. Craniopharyngiomas usually develop near the pituitary gland and hypothalamus. Because of this location, the tumor affects endocrine function. If the tumor is close to the optic nerve, vision may also be affected.
Treatment for craniopharyngioma may include surgery, radiation therapy, or both. Surgery alone may be used in selected cases when the tumor may be safely removed with limited side effects. Surgery is often needed to remove a portion of the tumor to reduce compression of the visual pathways or relieve obstruction of the fluid-filled (cerebrospinal fluid) pathways.
Surgery may include placement of a permanent catheter into the cystic part of the tumor. The catheter is attached to a reservoir from which fluid may be drained. The location of the tumor may limit how much of the tumor can be removed or drained.
Radiation therapy is used to treat residual tumor after surgery. Radiation therapy may be used alone in selected cases.
Radiation therapy is most often fractionated, or given in small doses called fractions. Most patients receive treatments Monday – Friday, 5 days per week for approximately 6 weeks. Radiation therapy is considered a one-time treatment. A repeat course of fractionated radiation therapy is rarely given.
In special cases, including patients with tumors that progress after radiation therapy, a single dose of radiation therapy (radiosurgery) may be used to treat craniopharyngioma. In radiosurgery, a higher dose of radiation is given to a focused area of the tumor.
A newer form of radiation therapy, proton beam radiation therapy, may have advantages over traditional radiation therapy using X-rays. However, this type of treatment is still being studied and is not available at every medical center.
Risk Factors and Causes of Craniopharyngioma
There are no known causes of craniopharyngioma. Research to learn more about gene changes associated with these tumors is ongoing. Craniopharyngioma is most often diagnosed in children between 5 and 14 years old. This tumor rarely occurs in children younger than 2 years old.
Signs and Symptoms of Cranipharyngioma
Symptoms of craniopharyngioma vary based on the tumor size and location. Symptoms may include:
- Changes in hormones and endocrine function. This may result in problems such as slowed growth and delayed puberty.
- Changes in vision
- Headache that is often worse in the morning and may go away after vomiting
- Confusion
- Nausea and vomiting
- Changes in energy levels, tiredness
- Problems in thinking and learning
- Change in personality and behavior
- Increased thirst or urination
- Low blood pressure
- Weight gain
- Increased or lost appetite
As the tumor grows, it may block the normal flow of cerebrospinal fluid. This causes a build-up of fluid within the brain known as hydrocephalus. The fluid causes the ventricles to widen and increases pressure on the brain (intracranial pressure). Many of the symptoms of craniopharyngioma are due to the increased pressure against brain tissue.
Diagnosing Craniopharyngioma
Doctors test for craniopharyngioma and effects of the tumor in several ways. These tests include:
- A health history and physical exam helps doctors learn about symptoms, general health, past illness, and risk factors.
- Blood serum chemistry, urine chemistry, and hormone studies are used to look at substances in the blood and urine.
Doctors may check serum and urine levels of electrolytes such as sodium as well as specific gravity (concentration of urine) to determine if there is diabetes insipidus. Doctors may check serum levels of alpha-feto protein (α-FP) and beta-human chorionic gonadotropin (β-hCG) to rule out the presence of a germ cell tumor which may sometimes be confused with craniopharyngioma. To test for the presence of abnormal hormones, blood levels measuring growth hormone, thyroid hormone, adrenocorticotropic hormone, and gonadotropin deficiencies or excesses may be evaluated.
- A neurological exam examines the function of the brain, spinal cord, and nerves. These tests measure different aspects of functioning including memory, vision, hearing, muscle strength, balance, coordination, and reflexes.
- Imaging studies including computed tomography (CT) and magnetic resonance imaging (MRI) create detailed pictures of the brain and spinal cord. Doctors can see the size and location of the tumor and better understand what areas of the brain might be affected. MRI is often preferred, as it generally provides a clearer picture of brain tumors.
- A biopsy may be performed to diagnose craniopharyngioma. In a biopsy, a small sample of the tumor is removed using a needle. A pathologist looks at the tissue sample under a microscope to identify the specific type of tumor. As an alternative, tumor cyst fluid may be assessed for diagnostic purposes. When surgery is not performed or biopsy is not conclusive, the presence of calcification on CT, in additional to the size, shape and location characteristics of the tumor may be diagnostic.
Craniopharyngioma in axial CT
Craniopharyngioma in axial MRI
Sagittal MRI shows size markings of a craniopharyngioma
Prognosis for Craniopharyngioma
There is no standard staging for craniopharyngioma. The tumor is described as newly diagnosed or recurrent.
Craniopharyngiomas are benign and very rarely spread to other parts of the brain. However, they can cause serious problems including changes in endocrine function and damage to the optic nerve. Treatment can be difficult due to the location of the tumor.
Survival rates for craniopharyngioma are estimated to be between 80 and 90% 10 years after diagnosis. However, long-term quality of life for patients with craniopharyngioma is an important consideration when planning treatments. Tumors that progress after radiation therapy are difficult to cure if surgery cannot be performed to remove the tumor entirely.
Treatment of Craniopharyngioma
Treatment depends on several factors including the size and location of the tumor, the child’s age, and features of the tumor. Treatments for craniopharyngioma include surgery and radiation therapy. There is no effective chemotherapy. In most cases, the approach to treatment of craniopharyngioma is less a decision of survival and more of quality of life. It is important that patients be treated by an experienced medical team including specialists in radiation oncology, neurosurgery, endocrinology, neurology, and ophthalmology. Doctors should discuss the risks and benefits of each treatment with families so that they can make informed decisions.
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The extent of surgery for craniopharyngioma is based on the size and location of the tumor as well as potential risks of surgery. In some cases, long-term control of the tumor is possible with surgery alone. However, surgery is often not able to remove the tumor completely. In addition, there are often serious complications with surgical tumor removal (radical surgery) due to the potential effects on important brain and endocrine functions.
Doctors may plan limited surgery that doesn’t fully remove the tumor. Instead, the primary goal in limited surgery is to treat symptoms or problems. In limited surgery, the surgeon is concerned with confirming the diagnosis, draining fluid from the cyst in the tumor, and relieving pressure on the optic nerve. Limited surgery is usually followed by radiation therapy.
In many cases, the surgeon will place a catheter into the cyst in the tumor. The catheter is a thin tube that drains fluid from the cyst. Removing this fluid helps many of the symptoms associated with the disease. The catheter may be temporary or permanent.
Different surgical techniques are used to reach the tumor. Surgeons may be able to access the tumor through transsphenoidal or endonasal surgery. This surgery is performed through the nasal passages and sinus cavity to reach the tumor. Or, surgeons may perform a craniotomy, or surgical opening in the skull. The surgical technique is based on the location of the tumor and goals of surgery.
Pros Cons Radical Resection
Avoid complications associated with radiation therapy
Acute injury including stroke, vision loss, diabetes insipidus and hormone deficiencies, and traumatic brain injury; long term effects including personality changes, diabetes insipidus and hormone deficiencies, morbid obesity
Limited Surgery + Radiation
Less risk to personality
Cognitive effects, hormone deficiencies, hearing loss, blood vessel effects including stroke, necrosis, secondary tumors (benign and malignant)
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Radiation therapy is used in addition to surgery, especially if limited surgery was performed. The type of radiation therapy used depends on the location of the tumor. Age of the child is an important consideration in the use of radiation. Radiation therapy is also used to treat recurrent disease after prior surgery that was considered radical.
Radiation therapy is most often fractionated, or given in small doses called fractions. Most patients receive treatments Monday – Friday, 5 days per week for approximately 6 weeks. Radiation therapy is considered a one-time treatment. A repeat course of fractionated radiation therapy is rarely given.
In special cases, including patients with tumors that progress after radiation therapy, a single dose of radiation therapy (radiosurgery) may be used to treat craniopharyngioma. In radiosurgery, a higher dose of radiation is given to a focused area of the tumor.
A newer form of radiation therapy, proton therapy, may have advantages over traditional radiation therapy using X-rays. However, this type of treatment is still being studied and is not available at every medical center.
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Chemotherapy is rarely used to treat craniopharyngioma.
Life after Craniopharynigioma
Most survivors of cranipharyngioma live with complications that affect quality of life, due to the tumor or its treatment.
These problems may include:
- Endocrine dysfunction related to harm to the pituitary and hypothalamus glands
- Loss of vision
- Cognitive problems
- Emotional problems
- Metabolic syndrome
- Vascular conditions such as aneurysm and stroke
The pituitary gland is called the “master gland” because it is responsible for many hormones and control of other glands. Abnormal pituitary function can lead to a number of problems. These problems may include obesity, poor lipid profile, lower bone mineral density, and lower fertility. These problems can occur even when the patient takes hormone replacement medicines.
Damage to the hypothalamus also results in hormone changes that affect quality of life. These problems include increased appetite, morbid obesity, and changes in behavior and emotions.
Metabolic syndrome is an important health issue that affects quality of life and longevity for survivors of childhood craniopharyngioma. This syndrome is a group of conditions including obesity, high triglyceride level, low HDL level (good cholesterol), high blood pressure, and high blood sugar. Metabolic syndrome is linked to heart disease, stroke, and diabetes.
Treatments for craniopharyngioma, including surgery and radiation therapy, increase a person’s risk of developing problems in blood vessels of the brain. This can lead to aneurysm and stroke. Patients are also at increased risk for seizures and cognitive impairments.
Children with craniopharyngioma need ongoing care by a multidisciplinary team to monitor disease progression, evaluate hormone levels and function, and address health problems related to the disease and/or treatments.
Patients can also benefit from psychosocial support during treatment and survivorship. Care team members representing Psychology, Child Life, Social Work, and other disciplines can assist with coping and adjustment concerns including risk for social isolation and depression.
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Reviewed: June 2018