A nonfunctioning pituitary adenoma (NFA) is a benign growth in the pituitary gland that does not produce any excessive hormone into the blood and is not cancerous. Non-functioning pituitary adenomas account for 15 percent of all pituitary adenomas, with approximately 70–90 cases per million people within the population.
Symptoms of a Nonfunctioning Pituitary Adenoma
These tumors do not result in symptoms based on excess production of hormones (e.g. substantial weight gain as seen in Cushing’s disease or enlargement of hands and feet as seen in acromegaly). Because of this, doctors can’t diagnose it until the tumor affects other structures, resulting in visual loss or headaches. In some cases, the tumor may compress the normal pituitary and cause loss of the pituitary’s normal role in controlling the reproductive, thyroid and adrenal gland function.
The earliest symptom of hormone deficiency is typically loss of sexual function in men (from low testosterone) and loss of menstrual periods in women. People may also experience fatigue from low thyroid or cortisol levels. Some tumors are discovered incidentally when the patient is assessed for other reasons (such as an MRI scan performed after a car accident).
Symptoms related to the tumor:
- Visual decline: blurred vision or difficulty with peripheral vision
Symptoms related to hormonal deficiency include:
- Growth hormone deficiency (low growth hormone)
- Growth failure in children
- Hypogonadism (low reproductive hormones)
- Delayed puberty in children
- Reduced or loss of sex drive
- Menstrual irregularities/loss of menstrual cycle
- Hypocortisolism (low cortisol)
- Weight loss
- Hypothyroidism (low thyroid)
- Sensitivity to cold
- Weight gain
- Personality changes
- Diabetes insipidus (low antidiuretic hormone)
- Frequent urination
- Excessive thirst
- Loss of vision is a progressive symptom (meaning it continues to get worse) and therefore, tumors that present with visual symptoms require treatment in order to, hopefully, improve vision and to prevent additional visual loss.
- Hormone deficiencies, such as thyroid hormone or cortisol, require immediate replacement of these hormones since these two hormones are necessary for life.
An endocrinologist will determine which blood tests are necessary to investigate whether there are pituitary hormone deficiencies.
Although a pituitary adenoma can be seen on a regular MRI, patients often require a more detailed imaging of the pituitary (pituitary protocol MRI) to determine the anatomy of the tumor and its relation to the optic nerves and the pituitary gland.
Patients with visual symptoms are often referred for formal visual testing by a neuro-ophthalmologist.
If you lose your vision you’ll need immediate treatment. With timely treatment, other you can avoid other longterm symptoms, such as the effects of hormonal deficiencies.
The first line of treatment remains surgical removal of the tumor.
There are no consistently effective medical treatments for this type of tumor. There are isolated reports of treatment with a dopamine agonist drug (bromocriptine, cabergoline) that showed some decrease in the size of the tumor. However, this occurred in a small number of patients.
If pituitary deficiencies are present before the surgery, hormone replacements will be prescribed to compensate for the loss of hormone production. This type of medication will not shrink or remove the tumor.
Although small tumors can often be followed without surgery, the treatment for large nonfunctioning adenomas is surgery to remove as much of the tumor as possible.
Effective surgical treatment can improve vision and prevent additional vision loss. The best results occur when an experienced pituitary neurosurgeon performs the surgery. Every patient should investigate this issue before deciding who should perform the operation.
Many patients have relief from headaches and marked improvement in visual function after surgery. Patients may require hormone replacements even if they did not require these before the surgery. At follow-up, all patients will undergo a complete hormonal evaluation to determine which hormone or hormones need to be replaced.
The size and location of your tumor will will determine whether or not you need radiation therapy.
Since many NFAs are large in size, they may have grown large enough to surround other structures such as the carotid artery or the optic nerves. In these cases, surgery alone can’t remove the entire tumor, so we use radiation therapy to shrink the remaining tumor..
Monitoring After Treatment
All types of pituitary adenomas, including a nonfunctioning adenoma, may recur at any time. For this reason you’ll need regular visits with your endocrinologist and neurosurgeon. Since there is no blood test to determine if a nonfunctioning adenoma has returned, you will need to have an MRI scan every year, for at least the first 5 years after surgery. If your tumor doesn’t recur, you can have your MRI every two years.
While a nonfunctioning pituitary adenoma is a benign tumor, it does require treatment and regular monitoring and follow up. With successful surgery and appropriate hormone replacement, you can live a normal life.
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Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.