Craniopharyngiomas are rare benign tumors. Less than 400 new cases are diagnosed in the United States each year. They may be located within the pituitary gland or above the pituitary gland. People with this condition are born with it, and the tumor may enlarge at any time.
These tumors generally come to attention either during childhood (5-15 years of age) or late adulthood (50-75 years of age). They are typically not diagnosed until they press on important structures around them, which causes symptoms. They are frequently large (over 2 cm) when detected and cause a variety of symptoms depending on the age at diagnosis, as well as their size and exact location.
Although craniopharyngiomas are benign tumors (not cancerous), their location can make them difficult to remove completely. A multidisciplinary approach is essential to the appropriate management and treatment of patients with craniopharyngiomas.
The exact cause of these tumors is not known. However, there is some thought that these tumors arise from a neoplastic transformation, meaning an abnormal development, of cells that did not go away during the fetal development of the pituitary and hypothalamus. The tumor is present at birth, but it may not cause a problem until childhood or adulthood.
Craniopharyngiomas can cause a wide variety of symptoms, but unlike pituitary adenomas, this type of tumor does not produce hormones. It does frequently interfere with normal pituitary gland function and may cause pituitary deficiencies. The exact symptoms depend on a number of factors including the age at diagnosis and the size and location of the tumor.
Symptoms by age
- Signs of increased intracranial pressure, including:
- Ocular palsies (abnormal eye movement)
- Visual disturbances
Older children and adults:
- Increased cranial pressure, also including
- Visual disturbances, including double vision and blurring
- Vomiting without nausea
- Altered level of consciousness
- Back pain
- Pituitary dysfunction and deficiencies
- Diminished growth velocity in children
- Hypogonadism (decreased libido, altered menstrual cycles) in adults.
- Diabetes Insipidus (a disorder of water balance with frequent urination and excessive thirst)
- High blood pressure
Symptoms by location and size
Nearly all craniopharyngiomas are found in or around the pituitary (or sella). Although very few are limited just to the sella, most tumors have at least a portion within the sella. A sizable minority of people have tumors that are located completely above the sella (suprasellar). Tumors that are limited to the sella do not cause visual deficits or symptoms of increased intracranial pressure. Instead, tumors confined to the sella will more often cause deficiencies in pituitary function. As tumors grow, they may compress the optic nerves, causing varying degrees of visual problems. Larger tumors may compress the brain and cause increased intracranial pressure or hydrocephalus.
A thorough history and physical examination is necessary and should evaluate potential endocrine, visual, and neurological deficits. An endocrinologist, neurosurgeon and neuro-ophthalmologist are often involved in the evaluation.
Tests and positive results include:
- Pituitary hormone blood tests: Deficiencies often indicate a positive result.
- Imaging of the pituitary: Presence of an abnormality will not only confirm a pituitary adenoma and provide other useful information. Two methods are generally used:
- Magnetic resonance imaging (MRI): This provides important information regarding the character of the tumor [solid, cystic (fluid-filled) or both] and its relation to important brain structures (visual pathways, blood vessels, third ventricle/hypothalamus).
- Computed tomography (CT): Can also play an important role in diagnosis and surgical planning. At times, a craniopharyngioma will be predominately cystic (fluid-filled). In this situation, a variety of other cyst types, including a Rathke’s cleft cyst, may be entertained. In general, the presence of calcifications (which are seen more easily on CT than MRI) confirms the diagnosis of craniopharyngioma and may alter the surgical plan.
- Visual field and acuity testing: Due to the size and location of craniopharyngiomas, visual abnormalities often arise. While visual disturbance does not confirm a diagnosis of a craniopharyngioma, a detailed exam is important to assess vision and the health of the optic nerves.
- Cognitive testing: Performed by a neuropsychologist.
A variety of treatments are available for patients with a craniopharyngioma. Because these tumors are highly variable, no single strategy is appropriate for all people. The ideal treatment strategy must be individualized for the specific tumor occurring in a specific person. Important considerations include a person’s age and whether there is evidence of pituitary, visual or neurological deficits. Important features of the tumor include the tumor size, location, character (cystic, solid, both) and relation to critical intracranial structures (blood vessels, optic pathways, hypothalamus). For instance, injury to the hypothalamus may cause hypothalamic obesity in which the satiety center is disrupted.
In general, medicines are not used to treat this type of tumor. There is limited data of the use of systemic chemotherapy in the treatment of craniopharyngioma; however, chemotherapy is not standard medical treatment for these types of tumors. Most patients require hormone replacement(s) because of damage to the normal pituitary gland by the tumor.
Complete surgical removal is considered the optimal strategy as long as it can be done without causing significant permanent neurological deficits. Depending on the person, the specific tumor and surgeon's preferences and experience, complete surgical removal may be performed by either a craniotomy or a transsphenoidal approach.
If complete surgical removal is not considered possible, a more conservative removal may be performed. This is often followed by radiation therapy or radiosurgery depending on the patient's age and the location of the remaining tumor. In selected cases of predominately cystic tumors, some patients may be treated with a less invasive drainage method, followed by a radioactive isotope or antineoplastic agent.
Evidence suggests that radiation therapy and radiosurgery provide effective tumor control in people with incompletely removed craniopharyngiomas.
Craniopharyngiomas can be treated effectively with surgical removal (depending on the size and location of the tumor). Because any type of pituitary tumor may recur, regular follow up with an MRI scan is necessary. If a recurrent tumor is found, additional treatment is necessary.