Craniopharyngiomas and pituitary adenomas are both types of tumors that begin growing in or around the pituitary gland. Although most of these tumors are benign, they can cause some symptoms.

The pituitary gland is a small, pea-sized gland that sits at the base of the brain.

Pituitary tumors are the second most common type of primary central nervous system tumors among all age groups, accounting for 10–25% of all tumors inside the skull. They are the most common type among adolescents and young adults.

Craniopharyngiomas are less common, with just 0.5 to 2 cases per million people each year.

Read on to learn more about these pituitary tumors.

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Although the vast majority of craniopharyngiomas and pituitary adenomas are benign, they can still cause symptoms.

Craniopharyngiomas

More specifically, craniopharyngiomas can cause compression-related symptoms, which may include:

  • limb weakness
  • difficulty walking
  • seizures
  • psychiatric symptoms, such as paranoid delusions
  • elevated intracranial pressure, causing headaches and nausea
  • hormonal imbalances, such as those regulating thirst and urination

Doctors refer to the pituitary gland as the “master gland” because of its importance to hormone function in the body. Therefore, most people with a craniopharyngioma that compresses the pituitary gland develop hormone deficiencies.

If the tumor presses on the hypothalamus, this can cause dysregulation of the hypothalamus. The hypothalamus controls the secretion of hormones from the pituitary gland and is responsible for many biological processes.

A 2019 study reported that if the hypothalamus is involved or injured during treatment, people commonly develop hypothalamic obesity, physical fatigue, and psychosocial problems.

Additionally, if the tumor compresses the optic nerves or optic chiasm, where the optic nerves cross, it can cause vision loss or blurry vision.

Craniopharyngiomas are difficult for doctors to access and treat because they are close to many critical structures within the brain. Therefore, people can also experience a range of symptoms resulting from treatment attempts.

Pituitary adenomas

Pituitary adenomas can cause the pituitary gland to secrete excessive levels of hormones. The exact hormone secreted will depend on which type of cell the tumor is affecting.

For instance, if the pituitary gland is secreting too much prolactin, this is a sign of a type of noncancerous pituitary tumor called a prolactinoma.

Symptoms related to excessive prolactin secretion can include:

Pituitary adenomas can also cause problems by putting pressure on surrounding tissues. A tumor can compress the pituitary gland itself, resulting in pituitary hormone deficiencies. It can also compress the optic nerves and optic chiasm, causing vision problems.

Additionally, some pituitary adenomas can be “silent” or non-functioning. This type of tumor does not secrete pituitary hormones but can still cause compression problems.

Craniopharyngiomas result from the malformation of cells in and around the pituitary gland as an embryo develops. There are two types: adamantinomatous and papillary.

Adamantinomatous craniopharyngiomas account for 86–89% of all craniopharyngiomas and are more common in children. They develop when cells from the craniopharyngeal duct, a bony channel between the pituitary and the nasopharynx, turn into tumor cells.

In contrast, papillary craniopharyngiomas usually affect adults. This type of tumor results from changes in the cells of the anterior — frontal lobe — pituitary gland and causes nests of squamous cells to form.

Doctors do not know the cause of either type of craniopharyngioma, but more than 70% of people with adamantinomatous craniopharyngiomas have variations in the CTNNB1 or APC genes.

There may also be a genetic cause in people with pituitary adenomas.

For instance, the American Cancer Society says that people with pituitary adenomas commonly have variations in the AIP, GNAS, USP8, USP48, and BRAF genes. These are acquired genetic variations rather than ones that run in families.

To diagnose a pituitary tumor, a doctor will take a person’s medical history and perform a physical exam. They will look for a combination of clinical signs, including:

  • headaches
  • vision problems
  • a reduced growth rate
  • increased thirst and urination
  • other signs of hormone deficiency

To confirm hormone deficiencies, they will order lab tests to check the levels of electrolytes in the blood. They will also test the levels of hormones that pituitary gland dysfunction can impact, including:

  • growth hormone
  • insulin-like growth factor 1
  • thyroid-stimulating hormone
  • free thyroxine
  • cortisol
  • follicle-stimulating hormone
  • luteinizing hormone
  • testosterone
  • estradiol
  • prolactin

Additionally, doctors can use imaging tests. A CT scan can check whether a tumor has calcified and an MRI scan can show whether fluid has collected inside a cystic tumor.

Treatment for craniopharyngiomas can include a combination of surgery, radiation therapy, and medication.

A surgeon may remove the whole tumor if there is no risk of damaging nearby structures.

One 2020 study emphasized the importance of aiming to remove as much of the tumor as possible while at the same time minimizing the risk of injuring the hypothalamus. Therefore, if the tumor is too close to important structures, the surgeon might not remove the whole tumor.

After surgery, a person will receive radiation therapy. Some people may also need hormone replacement therapy if they develop hypothalamic and pituitary gland dysfunction.

For pituitary adenomas, the treatment options are similar. Doctors may recommend:

  • surgery to remove the tumor
  • high-dose radiation therapy to kill the tumor cells
  • medication to shrink or destroy the tumor

With prompt and appropriate treatment, craniopharyngiomas have a 20-year survival rate of over 90%. Many doctors view these tumors as chronic conditions because of the high rate of recurrence, even when the surgeon has completely removed the tumor and nearby tissue.

Although these tumors are not fatal for most people, some can experience significant complications, such as:

  • stroke
  • heart problems
  • respiratory problems
  • chronic insufficiency of the hypothalamus
  • hormone deficiencies
  • seizures
  • cancer, in rare cases

Similarly, the outlook is positive for pituitary adenomas. Most people have a typical lifespan with treatment to control or remove the tumor. However, they may experience ongoing symptoms due to the effects of the tumor on their vision or hormones.

A person should contact a doctor if they or their child show new signs that could indicate a hormone deficiency, along with symptoms, including:

  • headaches
  • vision problems
  • increased thirst and urination
  • slowed growth rate

Craniopharyngiomas and pituitary adenomas are usually benign pituitary tumors. Both can cause a range of symptoms when they put pressure on the pituitary gland or other nearby structures.

Doctors do not know the exact cause of these tumors, but the cells become malformed during the embryonic stage of development, and genetic mutations could play a role.

Treatment usually involves surgery, radiation therapy, and sometimes, medication. Most people have a typical lifespan.