Pituitary Macroadenoma Treatment & Symptoms

What is it?
Prevalence and Incidence
Main Tumor Types
Transsphenoidal Tumor Resection
Gamma Knife Radiosurgery
Schedule Your Consultation

What is Pituitary Adenoma?

Adenoma is the medical term for any abnormal growth or tumor that occurs in one of the many glands of the body and a pituitary adenoma is a pituitary gland tumor. Pituitary adenomas are benign (non-cancerous) tumors.

The pituitary gland is the master controller of the endocrine system which is responsible for the overall hormonal balance of the body. While the glands that comprise the endocrine system are scattered throughout the body, the pituitary gland is a small, pea-sized gland located at the base of the brain. The pituitary gland is attached to the hypothalamus, a functional part of the brain that in turn controls the pituitary gland.

The pituitary gland is responsible for the production of many critical hormones including: growth hormone (GH) which controls normal growth; adrenocorticotropic hormone (ACTH) which stimulates the adrenal glands; prolactin which stimulates milk production in females after giving birth; sex hormones such as testosterone, LH, and FSH which controls sexual and reproduction; and thyroid stimulating hormone (TSH) which controls thyroid hormone levels. A pituitary adenoma will typically interfere with proper production of these hormones.

Pituaitary Adenoma Treatment & Symptoms

Approximately 1 in 1,000 people will develop a pituitary adenoma and many of these adenomas cause no problems or symptoms. These slow-growing benign tumors arise spontaneously without a known cause from the tissues of the pituitary gland and seldom are cancerous. About 10% to 15% of all intracranial tumors are pituitary adenomas.

Pituitary Macroadenoma Symptoms

Small adenomas less than 10 millimeters in size are called microadenomas while adenomas greater than 10 millimeters are called macroadenomas. Otherwise, adenomas are classified as hormone-producing or hormone-inactive adenomas based upon their impact on the activity of the pituitary gland. Hormone-producing adenomas cause the pituitary gland to secrete an excess amount of a hormone and disrupt the normal balance of hormones in the body. Hormone-inactive adenomas are larger tumors that, due to their size, may damage the pituitary gland or exert pressure on surrounding brain tissues.

The most common hormone-producing adenomas are named in conjunction with the hormone they stimulate:

ACTH-secreting pituitary adenomas cause secretion of excess cortisol by the adrenal glands and cause Cushing’s syndrome. Cushing’s syndrome caused by an ACTH-secreting pituitary adenoma is cased Cushing’s disease.

Growth hormone-secreting pituitary adenomas cause secretion of excess growth hormone and can result in acromegaly in adults and giantism in children. In both cases, individuals continue to grow and reach an unusually large size.

Prolactin-secreting pituitary adenomas, also called prolactinomas, primarily affect females. Excess production of the hormone prolactin shuts down menstrual periods, causes breast enlargement, and production of breast milk.

Thyroid stimulating hormone (TSH) producing pituitary adenomas are a rare form of pituitary adenomas that cause hyperthyroidism, an excess of thyroid hormone in the body.

Pituitary Gland Tumor Symptoms

The symptoms hormone-producing adenomas cause are related to the hormone that is affected by the tumor as already noted. Hormone-inactive adenomas exert pressure on surrounding brain structures and can produce a variety of symptoms depending upon the area of the brain affected by the tumor.

Compression of the pituitary gland by a hormone-inactive tumor can result some form of pituitary failure with one or more of the following pituitary tumor symptoms:

• Low blood pressure

• Fatigue

• Inability to handle stress

• Sexual dysfunction

Compression of the pituitary stalk which connects the pituitary gland to the hypothalamus can result in mildly elevated levels of prolactin, causing irregular menstrual periods in females. This condition is different from a prolactin-secreting pituitary adenoma.

A macroadenoma that grows upward from the pituitary gland can impact the optic chiasm, part of the pathway in the brain between the eye and the visual cortex. The visual cortex is the portion of the brain that ultimately controls eyesight. This type of pituitary adenoma results in:

• Blurry vision

• Loss of peripheral vision, called bitemporal hemianopsia

• Loss of color perception, the ability to distinguish colors

• Headache

Pituitary apoplexy can be a severe result of any type of pituitary adenoma. With pituitary apoplexy the adenoma bleeds into itself and causes a sudden headache accompanied by a loss in vision. Pituitary apoplexy is a medical emergency.

Pituitary Macroadenoma Diagnosis

A pituitary adenoma diagnosis is typically accomplished by an endocrinologist through sophisticated blood tests that measure applicable hormone levels along with MRI (magnetic resonance imaging) of the brain and pituitary gland.

Pituitary Tumor Treatment Without Surgery

Medical management with drugs through an endocrinologist is the first-line treatment for pituitary adenomas secreting prolactin. Pituitary tumors rarely require any other treatment. Medical management may also play a role, along with surgery, in acromegaly, Cushing’s disease, and pituitary failure (hypopituitarism). Otherwise, surgery to remove the adenoma is the treatment of choice. Some patients with incidentally discovered non-secretory adenomas may be best treated with observation alone.

Transsphenoidal Tumor Resection

Transsphenoidal tumor resection is the name of the surgical technique used to remove a pituitary adenoma. The surgeon enters the body through the nostrils and the sphenoid sinus cavity. The surgeon then creates a small hole in the bone at the back of the sinus cavity. This hole allows the surgeon to view the pituitary gland and the adenoma and ultimately remove the tumor.

The surgeon utilizes specially designed tools during a transsphenoidal tumor resection. Fluoroscopy, an imaging system that transfers a stream of images to a screen, assists the surgeon in inserting a tube through the nostril and into the sinuses. Inside the tube a high-powered surgical microscope magnifies the internal structures, giving the surgeon an enhanced image of the pituitary gland, the adenoma and the surrounding tissues. Depending on the size of the adenoma, it is removed intact or larger tumors are removed in small pieces. Removal is typically done by suction. The space left after the removal of a large tumor may be filled with body fat from the patient’s abdominal area.

Very large and very small pituitary adenomas each present their own challenges. A skilled surgeon is required to locate and remove a tiny tumor without damaging any pituitary gland tissue. On the other hand, portions of a large adenoma might not be completely visible through the small hole in the sinus cavity. In this case, the surgeon utilizes an endoscope, a fiber-optic instrument that allows the surgeon to see around corners, inside the brain.

Houston neurosurgeons at the Texas Spine and Neurosurgery Center also may use the latest in stereotactic or 3-dimensional neurosurgery techniques to aid in the removal of a pituitary adenoma. These techniques require the patient to undergo a specialized MRI scan typically the day before the surgery date. The images from this scan are used in conjunction with a 3-dimensional neuronavigation computer system that allows the neurosurgeon to track the location of instruments being used inside the brain during surgery.

Gamma Knife Radiosurgery

Gamma knife radiosurgery is the treatment of choice for recurrent pituitary adenomas, tumors that return after a successful transsphenoidal tumor resection, and for tumors that cannot be completely removed by surgery. Radiosurgery is a modern non-invasive technique for destroying benign and cancerous tumors. Radiosurgery destroys tissue through the precise concentration of radiation to the tumor, in this case the pituitary adenoma.

While Gamma Knife is the name of the instrument, there is no knife or cutting involved in the procedure. Before the procedure the patient’s head is fitted with a metal frame that is held in place by four pins. The metal frame provides fixed reference points for locating brain areas and the tumor. With the frame securely in place, the patient undergoes imaging scans of the brain. After the scans are complete, sophisticated computer software analyzes the images and prepares controlling information for the Gamma Knife unit.

The Gamma Knife treatment is similar to getting an MRI or CT scan. The metal head frame is fixed to the machine and the immobile patient slides into the treatment portion of the equipment. The Gamma Knife emits the required amount of radiation to the precise spot of the tumor without damaging any other tissues. The dosage and length of time of the treatment varies. Gamma Knife radiosurgery damages tumor cells so that they are unable to reproduce. It usually takes several weeks to months for the full results of this technique to shrink or destroy a tumor. The patient is usually able to return home shortly after treatment.

Dr. John Park is one of the few neurosurgeons in the area with specialized training in Gamma Knife radiosurgery. Patients who may be a candidate for this procedure should see him to obtain consultation. He will determine if you are a candidate for Gamma Knife treatment.

Schedule Your Pituitary Adenoma Consultation

Our Houston neurosurgeons are highly experienced at managing pituitary adenomas. Dr. Park and Dr. Bindal will discuss your condition during the consultation and inform you of the most appropriate treatment option to appease your pituitary adenoma symptoms. Contact our greater Houston neurosurgery center today to schedule your pituitary adenoma consultation – 281-313-0031.

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