What is the thyroid?
The thyroid is a gland in the neck. It has two type of cells that create hormones. Follicular cells make thyroid hormone, which affects heart speed, body temperature, and energy stage. C cells create calcitonin, a hormone that aid manages the height of calcium in the blood.
The thyroid is formed like a butterfly and lies at the front of the neck, beneath the voice box (larynx). It has two element, or lobes. The two lobes are divided by a thin part called the isthmus.
A healthy thyroid is a little larger than a quarter. It typically cannot be felt through the skin. A swollen lobe might appear or feel like a lump in the front of the neck. A swollen thyroid is called a goiter. Most goiters are cause by not enough iodine in the diet. Iodine is a essence found in shellfish and iodized salted.
What are symptoms of thyroid cancer?
Early thyroid cancer often does not cause symptoms. But as the cancer grows, symptoms may include:
* A lump, or nodule, in the front of the neck near the Adam's apple;
* Hoarseness or difficulty speaking in a normal voice;
* Swollen lymph nodes, especially in the neck;
* Difficulty swallowing or breathing; or
* Pain in the throat or neck.
How is thyroid cancer diagnosed?
If a person has symptoms that suggest thyroid cancer, the doctor may perform a physical exam and ask about the patient's personal and family medical history. The doctor also may order laboratory tests and imaging tests to produce pictures of the thyroid and other areas.
The exams and tests may include the following:
* Physical exam—The doctor will feel the neck, thyroid, voice box, and lymph nodes in the neck for unusual growths (nodules) or swelling.
* Blood tests—The doctor may test for abnormal levels (too low or too high) of thyroid-stimulating hormone (TSH) in the blood. TSH is made by the pituitary gland in the brain. It stimulates the release of thyroid hormone. TSH also controls how fast thyroid follicular cells grow.If medullary thyroid cancer is suspected, the doctor may check for abnormally high levels of calcium in the blood. The doctor also may order blood tests to detect an altered RET gene or to look for a high level of calcitonin.
* Ultrasonography—The ultrasound device uses sound waves that people cannot hear. The waves bounce off the thyroid, and a computer uses the echoes to create a picture called a sonogram. From the picture, the doctor can see how many nodules are present, how big they are, and whether they are solid or filled with fluid.
* Radionuclide scanning—The doctor may order a nuclear medicine scan that uses a very small amount of radioactive material to make thyroid nodules show up on a picture. Nodules that absorb less radioactive material than the surrounding thyroid tissue are called cold nodules. Cold nodules may be benign or malignant. Hot nodules take up more radioactive material than surrounding thyroid tissue and are usually benign.
* Biopsy—The removal of tissue to look for cancer cells is called a biopsy. A biopsy can show cancer, tissue changes that may lead to cancer, and other conditions. A biopsy is the only sure way to know whether a nodule is cancerous.
The doctor may remove tissue through a needle or during surgery:
- Fine-needle aspiration: For most patients, the doctor removes a sample of tissue from a thyroid nodule with a thin needle. A pathologist looks at the cells under a microscope to check for cancer. Sometimes, the doctor uses an ultrasound device to guide the needle through the nodule.
- Surgical biopsy: If a diagnosis cannot be made from the fine-needle aspiration, the doctor may operate to remove the nodule. A pathologist then checks the tissue for cancer cells.
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