A pituitary adenoma is an unusual growth that develops in the pea-sized pituitary gland, located at the base of the brain behind the nose. While some pituitary tumors produce excess hormones, nonfunctioning pituitary adenomas do not. These tumors can still cause significant health problems by growing and pressing on nearby structures.
Understanding Nonfunctioning Pituitary Adenomas
Nonfunctioning pituitary adenomas are benign growths originating from the cells of the pituitary gland. They are termed “nonfunctioning” because, unlike other pituitary adenomas, they do not secrete hormones in excess. These tumors typically do not spread to other parts of the body and often grow slowly.
These tumors can cause problems through what is known as a “mass effect.” The optic nerves, which are responsible for vision, or the remaining healthy pituitary gland tissue, can be affected by this compression. Most nonfunctioning pituitary adenomas are macroadenomas, meaning they are 10 millimeters or larger in diameter, at the time of diagnosis.
Recognizing the Symptoms
Symptoms of nonfunctioning pituitary adenomas often arise from their growth and pressure on surrounding tissues. Headaches are a common symptom. Vision problems can also occur, such as a loss of peripheral vision or double vision, which happens when the tumor compresses the optic chiasm.
The compression of the normal pituitary gland tissue can lead to a deficiency in various hormones, a condition known as hypopituitarism. This hormonal imbalance can manifest as symptoms like fatigue, general weakness, and changes in weight.
In women, this may lead to irregular menstrual cycles or a complete absence of periods, along with decreased libido. Men might experience erectile dysfunction, reduced libido, and a loss of body or facial hair due to low testosterone levels. Additionally, individuals may experience increased sensitivity to cold, dry skin, and a pale appearance.
Diagnosis and Treatment
Diagnosing a nonfunctioning pituitary adenoma typically involves a combination of imaging and laboratory tests. Magnetic Resonance Imaging (MRI) of the brain with contrast is the primary imaging modality used to visualize the tumor, determining its size and extension.
Visual field testing is also an important part of the diagnostic process, as it assesses for optic nerve compression and any resulting vision loss. Blood tests are conducted to identify deficiencies in hormones produced by the compressed normal pituitary gland, such as thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), luteinizing hormone (LH), follicle-stimulating hormone (FSH), and prolactin.
The primary treatment for symptomatic nonfunctioning pituitary adenomas is surgical removal. Transsphenoidal surgery, performed through the nose and sinus, is the most common approach, aiming to remove the tumor and relieve pressure. In cases where surgery cannot completely remove the tumor or is not feasible, radiation therapy, such as stereotactic radiosurgery, may be used to control tumor growth. For small, asymptomatic tumors that are not actively growing, a “wait-and-see” approach involving regular monitoring with MRI scans may be recommended.
Living with a Nonfunctioning Pituitary Adenoma
After diagnosis and treatment, ongoing monitoring is a regular part of living with a nonfunctioning pituitary adenoma. This includes periodic MRI scans to check for any recurrence or growth of the tumor. The frequency of these scans may vary, often annually for the first few years, then less frequently if stable.
If the pituitary gland’s function remains impaired after treatment, hormone replacement therapy may be necessary. This involves taking medications to replace hormones the pituitary gland is no longer producing in sufficient amounts. While some patients may experience improvement in hormone deficiencies after surgery, others may require lifelong hormone replacement. With appropriate management, many individuals can lead normal lives.