These pituitary tumors produce too much thyroid-stimulating hormone (TSH, also called thyrotrophin), causing the thyroid gland to become overactive (hyperthyroidism). TSH-producing tumors are among the least common types of pituitary tumors.
Symptoms
TSH-producing tumors may cause the following signs and symptoms:
- rapid heart rate
- tremors
- unexplained weight loss
- increased appetite
- feeling too warm or hot
- trouble falling asleep
- anxiety
- frequent bowel movements
- a lump in the front of the neck (due to an enlarged thyroid gland).
Diagnosis
If your doctor suspects a TSH-producing tumor, a blood test may be ordered to measure your level of TSH and thyroid hormones. MRI may also be used to visualize the tumor.
Treatment
Surgery to remove the tumor is the primary therapy for TSH-secreting tumors. Surgery for pituitary tumors is often performed through a minimally invasive approach called transphenoidal transnasal resection, whereby the surgeon removes the tumor through an incision in the nasal passage. In cases where the tumor is too large to be removed through this approach, the surgeon performs a craniotomy, removing the tumor through an incision in the front of the skull.
If surgery alone is not curative, you may also have radiation therapy. Radiosurgery, or stereotaxic radiosurgery, is one type of external radiation therapy that uses special equipment to give a single large dose of radiation to a tumor. Intensity-modulated radiation treatment (IMRT) is another type of radiation therapy that uses radiation beams of varying intensity created to match specific tumor angles and shapes so that the tumor is targeted as precisely and uniformly as possible. This helps to reduce the damage to delicate structures in the area, such as the optic nerves.
Some patients receive injections of octreotide acetate (Sandostatin®). Given just once a month, this long-acting medication works by suppressing TSH production.
Follow-Up
Your doctor will see you periodically and perform certain tests to ensure that your pituitary tumor has not returned. If medication is part of your treatment, you may need to take it for the rest of your life to prevent tumor recurrence.
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