The pituitary gland is a small, pea-sized endocrine organ situated at the base of the brain, resting in a bony pocket called the sella turcica. This gland is responsible for producing and regulating several hormones that control growth, metabolism, reproduction, and stress response throughout the body. A pituitary tumor is an abnormal growth arising from the cells of this gland, and the vast majority of these growths are noncancerous, slow-growing masses known as pituitary adenomas. Treatment for a pituitary tumor is highly individualized, depending on the tumor’s size, whether it secretes excess hormones, and the symptoms it causes.
When Intervention is Necessary
Many small, non-functional tumors are simply monitored over time. Intervention becomes necessary when the tumor is either large enough to physically compress surrounding structures or when it produces an excessive amount of a specific hormone. Tumors are classified by size, with microadenomas being less than 10 millimeters and macroadenomas being larger than 10 millimeters. The latter are more likely to cause problems due to their mass.
The most concerning mass effect is pressure on the optic chiasm, which can lead to progressive vision loss, often affecting the peripheral visual fields. Intervention is also required for functional tumors that oversecrete hormones, causing specific diseases regardless of their size. For instance, tumors secreting Adrenocorticotropic Hormone (ACTH) lead to Cushing’s disease, while those secreting growth hormone cause acromegaly.
Primary Surgical Approaches
Surgery is often the preferred initial treatment for most pituitary adenomas, especially those causing vision loss or hormone overproduction that cannot be managed with medication. The two main surgical methods employed are transsphenoidal surgery and craniotomy, with the choice depending on the tumor’s size, location, and invasiveness.
Transsphenoidal Approach
The transsphenoidal approach is the most common method, allowing the surgeon to reach the pituitary gland through the nasal cavity and the sphenoid sinus. This technique avoids manipulating or cutting into the brain itself, resulting in less pain, a faster recovery, and no visible external scarring. Surgeons use either a traditional operating microscope or a newer, minimally invasive endoscope, which provides a wider, magnified view of the surgical field.
Craniotomy
A craniotomy, which involves opening a section of the skull, is reserved for more complex cases. This approach is necessary when the tumor is very large, has spread significantly outside the bony confines of the sella turcica, or has extensively invaded nearby structures like the cavernous sinus. While craniotomy offers a broader field of view for complex tumors, it is a more invasive procedure and carries a greater risk of temporary or permanent pituitary dysfunction compared to the transsphenoidal route.
Non-Surgical Treatment Options
Medication management and radiation therapy are used as alternatives or complementary treatments to surgical removal of pituitary tumors. Drug therapy is particularly effective for certain functional tumors, often serving as the first-line treatment.
Medication Management
Prolactinomas, which secrete excess prolactin, are usually treated with dopamine agonists like cabergoline or bromocriptine, which can shrink the tumor and normalize prolactin levels without the need for surgery. For tumors that secrete growth hormone or ACTH, medications such as somatostatin analogs can be used to decrease hormone production. Medication can also be used to block the effects of excess hormones in the body, such as drugs that inhibit cortisol production in Cushing’s disease.
Radiation Therapy
Radiation therapy is another non-surgical option, most often used for tumors that remain after surgery, those that recur, or those that cannot be safely removed. Highly focused techniques, such as Stereotactic Radiosurgery (SRS) or Gamma Knife, deliver a high dose of radiation precisely to the tumor area, minimizing damage to surrounding healthy brain tissue. This treatment works by damaging the tumor cells’ DNA, stopping their growth or eventually destroying them, although the effect on tumor control or hormone production can take months to years to fully manifest.
Recovery and Long-Term Follow-Up
The recovery period following pituitary surgery varies depending on the approach, with a typical hospital stay of two to three days after transsphenoidal surgery. Patients may experience temporary side effects like sinus congestion, fatigue, or altered taste and smell for a few weeks. Surgeons generally advise patients to avoid blowing their nose for several weeks.
A central component of long-term care is endocrine monitoring, which involves regular blood tests to check hormone levels. The pituitary gland’s function may be temporarily or permanently compromised after treatment, potentially leading to a deficiency in one or more hormones. Patients often require hormone replacement therapy, such as hydrocortisone for cortisol deficiency or thyroid hormone.
Lifelong follow-up is recommended for most patients, involving regular appointments with an endocrinologist and neurosurgeon. Imaging, typically with magnetic resonance imaging (MRI), is performed periodically in the months and years following treatment to monitor for any tumor recurrence or regrowth.