What Is Gonadotropin Secreting Pituitary Tumors

[Tyler Bannowsky]

Pituitarytumors are unusual growths that develop in the pituitary gland. This gland is an organ about the size of a pea. It's located behind the nose at the base of the brain. Some of these tumors cause the pituitary gland to make too much of certain hormones that control important body functions. Others can cause the pituitary gland to make too little of those hormones.

Most pituitary tumors are benign. That means they are not cancer. Another name for these noncancerous tumors is pituitary adenomas. Most adenomas stay in the pituitary gland or in the tissue around it, and they grow slowly. They typically don't spread to other parts of the body.

Pituitary tumors are different from pituitary cysts. A cyst is a sac that may be filled with air, fluid or other material. A tumor is an unusual mass of cells that may grow over time. Cysts may form on or near the pituitary gland, but they are not tumors or adenomas.

Not all pituitary tumors cause symptoms. Sometimes these tumors are found during an imaging test, such as an MRI or a CT scan, that is done for another reason. If they don't cause symptoms, pituitary tumors usually don't need treatment.

Pituitary tumor symptoms may be caused by a tumor putting pressure on the brain or on other parts of the body nearby. Symptoms also can be caused by a hormone imbalance. Hormone levels can rise when a pituitary tumor makes too much of one or more hormones. Or a large tumor that disrupts the way the pituitary gland works may cause hormone levels to fall.

Functioning pituitary adenomas typically make a large amount of one hormone. That exposes the body to high levels of that hormone. Rarely, a pituitary adenoma may make more than one hormone. The following types of functioning pituitary adenomas cause different symptoms depending on the hormones they make.

Pituitary tumors that make adrenocorticotropic hormone are called corticotroph adenomas. Adrenocorticotropic hormone, also called ACTH, causes the adrenal glands to make the hormone cortisol. ACTH tumors trigger the adrenal glands to make too much cortisol. This causes a condition called Cushing disease. Cushing disease is one cause of Cushing syndrome.

Pituitary tumors that make growth hormone also are called growth hormone-secreting tumors or somatotroph adenomas. Too much growth hormone leads to a condition known as acromegaly. Acromegaly can cause:

It's uncommon for these adenomas to make too many hormones that then trigger symptoms. Instead, symptoms from these adenomas usually are due to tumor pressure. If symptoms do happen because of too much LH and FSH, they affect women and men differently.

Pituitary tumors that make thyroid-stimulating hormone are called thyrotroph adenomas. They also may be referred to as thyroid-stimulating hormone-secreting tumors. They cause the thyroid gland to make too much of the hormone thyroxine, also called T-4. That leads to a condition called hyperthyroidism, also known as overactive thyroid disease. Hyperthyroidism can speed up the body's metabolism causing many symptoms. Some of the most common include:

If you develop symptoms that might be associated with a pituitary tumor, see your health care provider. Treatment for pituitary tumors often can bring hormones back to a healthy level and ease symptoms.

Although rare, some pituitary tumors are hereditary. That means they run in families. In particular, the hereditary disorder multiple endocrine neoplasia, type 1 (MEN 1) can cause pituitary tumors. If MEN 1 runs in your family, talk to your health care provider about tests that may help find a pituitary tumor early.

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The pituitary gland is a small organ about the size of a pea. It's located behind the nose at the base of the brain. Despite its small size, the pituitary gland has an effect on nearly every part of the body. The hormones it makes control important body functions, such as growth, blood pressure and reproduction.

The cause of uncontrolled cell growth in the pituitary gland, which creates a tumor, remains unknown. In rare cases, pituitary tumors can be caused by genes you've inherited. But most have no clear hereditary cause. Still, scientists think that changes in genes may play an important role in how pituitary tumors develop.

Most people who get pituitary tumors don't have any factors that put them at higher risk of developing these tumors. Environment and lifestyle choices don't seem to have an effect on a person's risk of pituitary tumors.

If a pituitary tumor presses on part of the brain called the medial temporal lobe, it may lead to a seizure. This type of seizure is known as a focal seizure with impaired awareness. These seizures involve a change in or loss of consciousness or awareness. If you have one of these seizures, you may seem to be awake. But you stare into space and don't respond as you typically would to the environment around you. You may not remember the seizure after it happens.

Gonadotroph adenomas are the most common type of nonfunctional pituitary adenomas. However, functioning gonadotroph adenomas causing clinical manifestations are rare. We present the case of a 42-year-old man with an incidental finding of a pituitary gland mass. A pituitary MRI revealed a 3 cm macroadenoma, and laboratory investigations revealed elevated follicle-stimulating hormone (FSH) and total testosterone levels. A diagnosis of functioning FSH-secreting pituitary adenoma was considered, with possible concomitant luteinizing hormone secretion, given the elevated testosterone, prompting further evaluation. Testicular ultrasound showed bilaterally enlarged testicles, and visual field testing revealed a monocular superior temporal defect. Transsphenoidal resection of pituitary adenoma was the treatment of choice. Histopathology assessment confirmed the diagnosis of gonadotroph-secreting adenoma, with positive staining for FSH. Within the 12-week postoperative period, FSH and testosterone levels normalized, and the patient experienced significant improvement in vision, along with the resolution of macroorchidism. While functional gonadotroph adenomas are rare, patients can present with a wide range of symptoms that are often unnoticeable due to their slow development. Careful evaluation can help guide multidisciplinary management to achieve full remission.

On examination, the patient had testicular enlargement, exceeding the maximum 25 cm3 measurement of the Prader orchidometer. Clinical assessment of the visual fields using the confrontational method revealed a defect of the temporal field vision affecting only the left eye. Regarding the COVID-19 diagnosis, the patient presented to the hospital with a fever, and a nasopharyngeal swab for SARS-CoV-2 PCR was obtained, yielding a positive result. The patient was admitted to the COVID-19 ward, where he was treated conservatively with antipyretics and supplemental oxygen; he did not receive steroids for treatment. Then, he was transferred to the medical ward for further evaluation of the pituitary adenoma.

Visual acuity testing was unremarkable. Visual Field testing, using a 30-2 Humphrey visual field (HVF) analyzer was performed and revealed a monocular superior temporal defect affecting the left eye. Right eye findings were normal.

The patient underwent transsphenoidal resection of the pituitary adenoma in July 2020. He did not receive glucocorticoids preoperatively despite borderline low cortisol levels but was monitored closely postoperatively. Histopathology assessment confirmed the diagnosis of gonadotroph-secreting adenoma, with positive immunostaining for FSH. Immunostaining was rare for LH and negative for ACTH, TSH, prolactin, and growth hormone (Fig. 3).

Histopathology of the pituitary tumor shows different growth patterns within the tumor, including nesting pattern (A), columns and cords (B), and rosette/papillary formation (C) (low power view). Tumor cells are monomorphic and show a chromophobic cytoplasm and a nucleus with stippled chromatin (D) (high power view). FSH immunostaining show strong cytoplasmic positivity in the majority of tumor cells (E). LH stain is scattered and patchy (F).

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