Pituitary tumors are abnormal growths that develop in the pituitary gland, a small organ located at the base of the brain, just behind the nose. There is often confusion about whether these growths are considered brain tumors due to their location within the skull. This article will explore the nature of pituitary tumors, their relationship to the brain, and their common symptoms, detection, and treatment.
Understanding Pituitary Tumors
The pituitary gland, often referred to as the “master gland,” is a pea-sized organ situated in a bony hollow called the sella turcica, at the base of the skull. It produces and releases hormones that regulate numerous bodily functions, including growth, metabolism, blood pressure, and reproduction.
Most pituitary tumors are benign, meaning they are non-cancerous and typically do not spread to other parts of the body. These growths are also known as pituitary adenomas. They usually grow slowly and tend to remain within the pituitary gland or the surrounding tissues.
Pituitary tumors are broadly categorized into two main types: functioning and non-functioning. Functioning adenomas produce excess hormones, leading to various symptoms depending on the specific hormone affected. Non-functioning adenomas, on the other hand, do not produce hormones but can cause symptoms due to their size and pressure on nearby structures.
Are Pituitary Tumors Brain Tumors?
While the pituitary gland is located within the skull, beneath the brain and above the nasal passages, it is anatomically distinct from brain tissue itself. The pituitary gland sits in a bony space, and the optic nerves pass directly above it.
Despite not originating from brain tissue, pituitary tumors are often managed by neurosurgeons or neuro-oncologists due to their intracranial location. Their proximity to the brain and structures like the optic nerves means a growing tumor can exert pressure, potentially affecting brain function or vision. Thus, while not strictly tumors of the brain, they are considered a type of intracranial tumor due to their location and potential impact within the skull.
The medical community sometimes classifies pituitary gland tumors as primary brain tumors. However, some organizations emphasize the distinction, noting that while in close proximity, the pituitary is separate from the brain. This distinction is important for patients, as being told they have a “brain tumor” can cause significant distress, even though most pituitary tumors are benign.
Common Symptoms and Health Impacts
Pituitary tumors can cause a variety of symptoms, generally falling into two categories: those caused by the tumor’s size and those caused by hormonal imbalances. Symptoms often arise when the tumor grows large enough to press on surrounding structures, known as a mass effect.
Mass effect symptoms include headaches. Vision problems are also common with larger pituitary tumors, due to pressure on the optic nerves. Other potential mass effect symptoms include dizziness, nausea, vomiting, and changes in peripheral vision.
Hormonal imbalances occur when functioning tumors produce too much of a specific hormone, or when a tumor’s growth inhibits the pituitary gland’s normal hormone production, leading to a deficiency. For instance, excess growth hormone can lead to acromegaly in adults, causing enlarged hands, feet, and facial features. An overproduction of prolactin can result in milky discharge from the nipples (galactorrhea) and reproductive problems. Conversely, a deficiency in certain hormones, like thyroid-stimulating hormone (TSH), can lead to symptoms of an underactive thyroid, such as fatigue and weight gain.
Detection and Treatment Approaches
Detecting pituitary tumors often involves a combination of diagnostic methods, as many are small, grow slowly, and may cause no symptoms or mimic other conditions. A healthcare provider will begin with a detailed medical history and a physical examination.
Blood tests are a primary diagnostic tool, revealing abnormally high or low levels of hormones produced or regulated by the pituitary gland. For example, blood tests can detect excessive levels of cortisol, prolactin, or growth hormone, indicating a functioning pituitary adenoma. Urine tests may also be used, particularly to detect high levels of ACTH, which can lead to Cushing’s disease.
Imaging techniques are crucial for pinpointing the tumor’s location and size. Magnetic Resonance Imaging (MRI) is the preferred imaging method due to its ability to provide detailed images of soft tissues and detect small tumors. A Computed Tomography (CT) scan may also be used, particularly for surgical planning. Vision testing is often performed to assess any impact on eyesight, especially peripheral vision, which can be affected by tumors pressing on the optic nerves.
Treatment for pituitary tumors varies depending on the tumor’s type, size, location, and whether it is causing symptoms.
Watch-and-Wait
A “watch-and-wait” approach may be suitable for small, non-symptomatic tumors that do not produce excess hormones.
Medications
Medications can be used to shrink certain types of tumors or to manage hormone levels. For instance, drugs can block the overproduction of hormones or replace deficient hormones.
Surgical Removal
Surgical removal is a common treatment option, especially for larger tumors causing mass effect symptoms or for functioning tumors that do not respond to medication. The most frequent surgical approach is transsphenoidal surgery, where the tumor is removed through the nasal passages, often using an endoscope for a minimally invasive procedure.
Radiation Therapy
Radiation therapy, which uses high-dose X-rays to destroy tumor cells, may be considered if surgery is not feasible, or if the tumor cannot be completely removed, or if it recurs.
A team of specialists, including neurosurgeons, endocrinologists, and radiation oncologists, collaborate to determine the most appropriate treatment plan.