Thyroid-Stimulating Hormone Tumor
Thyroid-stimulating hormone tumors are a type of pituitary adenoma that can either cause excessive thyroid hormone production (hyperthyroidism) or insufficient thyroid hormone production (hypothyroidism).
How common are thyroid stimulating hormone (TSH) tumors?
Thyroid-stimulating hormone adenomas are extremely rare; they account for only one percent of all pituitary adenomas. Most (about 70 percent) are macroadenomas, that is, their diameter is greater than 10 mm.
How are thyroid-stimulating hormone (TSH) tumors diagnosed?
If your doctor suspects a TSH tumor or other pituitary or endocrine disorder based on your symptoms, blood tests for elevated TSH and thyroid hormone levels can confirm the diagnosis. If these blood tests confirm a thyroid disorder, magnetic resonance imaging (MRI) or computed tomography (CT) can confirm the presence of an adenoma and provide a roadmap for surgical treatment.
Most symptoms of a TSH-producing tumor are caused by overstimulation of the thyroid gland to produce too much thyroid hormone (hyperthyroidism).
If you have a TSH adenoma, you may experience the following:
- Weight loss
- Rapid heartbeat (palpitations)
- Hand tremors
- Difficulty sleeping
- Frequent bowel movements
- Decreased menstrual flow or absence of menstruation
Other symptoms of pituitary tumors (not just TSH adenomas) can include:
- Visual loss
Surgery is the best form of treatment and the only way to achieve a cure. Your surgeon will gain access to your pituitary gland using the transsphenoidal approach—so named because the route your surgeon takes crosses, or transects, your sphenoid bone. This bone is located behind your nose mostly within your skull.
Using precise surgical instruments, your surgeon will make an incision through your nasal cavity to open your sphenoid bone. Once your surgeon accesses your sphenoid sinus (the air-filled area behind the sphenoid bone), further incisions will be made until a hole is created in the sella turcica—the bone that cradles and protects your pituitary gland.
After your surgeon identifies the tumor, removal can proceed. Your surgeon will use high magnification to readily distinguish normal pituitary tissue from the TSH adenoma.
Once the tumor has been removed, your surgeon will clean the tumor cavity and seal it.
At Barrow Neurological Institute at Dignity Health St. Joseph’s Hospital and Medical Center, we specialize in two types of surgery for TSH adenomas: microsurgery and endoscopic surgery.
- Microsurgery uses an operating microscope to help your surgeon distinguish between structures in and around your pituitary gland.
- Endoscopic surgery uses small instruments to help your surgeon remove your tumor in small pieces.
Both surgeries aim to minimize trauma to the tissue around your pituitary gland while facilitating a speedy recovery with as little pain or discomfort as is possible. Each technique has its own inherent advantages and disadvantages, and your surgeons will work with you to help determine which is the best fit for you.
Most patients are able to return home the day after their surgery for removing a TSH adenoma, and nasal packing is seldom required.
Gamma Knife radiosurgery is a highly advanced form of radiotherapy that is used to achieve similar results to the traditional surgical techniques described above. However, with Gamma Knife it can take several years for thyroid-stimulating hormone levels to return to normal, rather than days or weeks as with traditional surgery.
The ‘knife’ in this surgery is actually made up of many small beams of radiation focused on a single point. Each individual beam is too weak to damage healthy tissue, but at the point where all beams converge they deliver a dose of radiation that is lethal to the tumor.
Gamma Knife is an outpatient procedure, does not involve any incisions, and requires only brief sedation under general anesthetic.
A class of drugs known as somatostatin analogues can be used to decrease the effectiveness of thyroid-stimulating hormone (TSH) in patients who do not respond to surgery or radiation therapy.
Octreotide, a different type of drug than somatostatin analogues, has restored baseline levels of TSH in the blood in almost 80 percent of patients studied. It has shrunk TSH adenomas in slightly more than half of the patients studied.
- Date of last review: January 24, 2017
- Author: Andrew S. Little, MD