A pituitary tumor that secretes a hormone called thyroid-stimulating hormone (TSH) is called a thyrotropinoma (or sometimes a TSHoma). An excess of amount of thyroid hormone causes hyperthyroidism, which can be a serious medical condition.
Often, patients experience the typical symptoms of hyperthyroidism. Sometimes, patients will experience mild symptoms or even none at all.
Symptoms of hyperthyroidism include:
- Increased perspiration
- Heart racing
- Hand tremors
- Difficulty sleeping
- Thinning of the skin
- Fine, brittle hair
- Muscular weakness
- More frequent bowel movements
- Weight loss
- In women, lighter and less frequent menstrual flow
TShoma Symptoms: Thyroid Storm
Thyroid storm is a rare but severe complication of hyperthyroidism, requiring prompt treatment and hospitalization. Thyroid storm may occur when a thyrotoxic patient becomes very sick or physically stressed.
• Symptoms can include:
- Increase in body temperature to over 40 degrees Celsius (104 degrees Fahrenheit)
- Vomiting, diarrhea
In addition to hyperthyroidism, you may experience symptoms including:
- Diffuse goiter
- Menstrual disturbances
- Breast milk production (galactorrhea)
Rarely, patients with thyrotropinomas experience tumor mass effect, caused by large pituitary tumors (macroadenomas). In addition to the severe hormonal effects related to hyperthyroidism, the large tumor can compress adjacent structures leading to:
- Vision loss. This occurs when macroadenomas grow upward into the brain cavity, compressing the optic chiasm.
- A loss of the outer peripheral vision, called a bitemporal hemianopsia
- When severe, a patient can only see what is directly in front of them.
- Many patients do not become aware of their visual loss until it is quite severe.
- Other visual problems can include:
- Loss of visual acuity (blurry vision), especially if the macroadenoma grows forward and compresses an optic nerve.
- Colors not perceived as bright as usual
Diagnostic procedures include:
- Hormone testing
- Imaging scans
Hormone Testing for TSHoma
We use hormone tests to determine if there are elevated levels of thyroxine (T4) and thyrotropin (TSH). A neuro-endocrinologist, specializing in pituitary tumors, may be required in complex cases.
A magnetic resonance imaging (MRI) of the pituitary gland can be done to detect tumors.
Managing thyrotropinomas can be challenging. The most effective treatments involve the care and expertise of a multidisciplinary team, with close collaboration between the neurosurgeon and the endocrinologist. Surgery is usually needed, and the hyperthyroidism must be carefully managed prior to and during surgery to prevent serious complications.
Treatment options include:
- Radiation Therapy
Surgery for TSHoma
Surgically removing the tumor, or tumors, offers the best chance for a cure.
- If the tumor has invaded beyond the confines of the sella (the space where the normal pituitary gland sits), the chance for a cure is lower.
- The first surgery offers the greatest chance of cure; the cure rate with a second or third surgery is much lower.
Invasive and very large tumors may require additional therapy, including removal of the thyroid gland or stereotactic radiation of the pituitary tumor.
Medical Management of TSHoma
Anti-thyroid drugs are drugs that inhibit the production of thyroid hormones. These medications may take weeks to become effective. The dosage may also change over a period of months, until the optimal dosage is obtained.
Examples of anti-thyroid medication include:
- Beta blockers
Beta blockers are typically used to treat high blood pressure but can help reduce rapid pulse associated with the sensation of palpitations, and decreasing tremor and anxiety.
These drugs do not treat hyperthyroidism or any of its long-term effects.
Radiation Therapy for TSHoma
Some tumors cannot be removed surgically, and may not respond to medications. Radiation therapy can be effective in controlling the growth of these tumors.
Stereotactic radiosurgery is also indicated. This carefully sculpted radiation beam is able to deliver a high dose of radiation to the target. The surrounding brain structures receive only a fraction of the radiation and are typically unharmed, with the exception of the pituitary gland.
A consequence of radiation treatment is that it can cause delayed pituitary failure. This typically occurs several years after treatment. It is important that you continue your follow-up care with an endocrinologist, who can monitor your progress and any changes. You may require hormone replacement therapy.