A pituitary adenoma is a benign growth hat occurs in the pituitary gland. They are small tumors and are often undiagnosed. They are usually non cancerous and will not spread outside of the skull. Tumors can be nonfunctioning or functioning. There are more than one type of functioning pituitary tumors. Each tumor is classified based on the hormone that is secreted. Tumors in the pituitary can create excess prolactin, growth hormone, adrenocorticotropin or the hormone thyroxine. Functioning tumors that produce adrenocorticotropin trigger the adrenal gland to produce extra corticoid steroids which can lead to the condition Cushing’s Syndrome. A pituitary microadenoma is a benign growth that is smaller than 10 millimeters in size. The majority of tumors are microadenomas. A macroadenoma is a benign growth that is larger than 10 millimeters in size.
The pituitary gland sits in the middle of the sella turcica and directly beneath the optic nerves. When the gland enlarges, visual disturbances or headaches can occur. Each type of adenoma produces different symptoms based on the hormone that is being made and based on size. Symptoms can range from restlessness, vomiting, dizziness, and tiredness. The most common pituitary tumors are those that release prolactin and can cause side effects of infertility, loss of sexual interest, and changes in menstruation. Each type of adenoma will result in a completely different set of symptoms and will guide a physician in the proper diagnosis. The most common side effects reported are headache, fatigue, low blood pressure, nausea or vomiting, constipation, seizures, or unexpected weight loss or gain.
Diagnosis of adenomas is made after discussing medical history, current medications, family medical history, and physical examination for signs. Tests can include blood tests for hormone measure, CT scans, eye exams, and sinus sampling. Generally a MRI is ordered first to check for the progression of the tumor. Examining the size of the tumor as well as the damage to surrounding areas and location will give the physician the best idea of which treatment options are best.
The exact cause of an adenoma in the pituitary is unknown. Some can be inherited and some are associated with changes in DNA. An over exposure to cancer causing substances can also result in a tumor. Family medical history that shows these tumors increases the risk of development. Those with other conditions include high blood pressure, kidney stones, diabetes, and thyroid disease have an increased risk in developing these tumors.
Observation, medications, and surgery are the most common treatments used for pituitary adenoma. Treatment is only considered for tumors that grow or cause symptoms. Around 70% of tumors are nonfunctioning and do not require treatment. Medications that block hormone secretion can be useful in shrinking some tumors. Surgery is an option but the type of tumor determines how effective the procedure will be. Transphenoidal endoscopic tumors are removed through the nasal passage. More complicated or large tumors can be removed through an incision in the skull. Chemotherapy and radiation are options for treatment of a pituitary adenoma if the tumor has spread or persist.