Papillary carcinoma of the thyroid is the most common cancer of the thyroid gland.

See also: Thyroid cancer

About 75-85% of all thyroid cancers diagnosed in the United States are papillary carcinoma. It is more common in women than in men. It may occur in childhood, but is typically seen in people between age 20 and 40. 

The cause of this cancer is unknown. A genetic defect may be involved.

High-dose external radiation to the neck increases the risk of developing thyroid cancer. Papillary thyroid cancer in children has also been linked to atomic bomb testing in the Marshall Islands and the 1986 Chernobyl nuclear disaster in the Ukraine.

Radiation given by an I.V. during medical tests and treatments does not increase the risk of developing thyroid cancer.

Thyroid cancer usually begins as a small bump (nodule) in the thyroid gland. However, it should be emphasized that most thyroid bumps are harmless and noncancerous (benign).

If you have a lump on your thyroid, your doctor will order blood tests and an ultrasound  of the thyroid gland. 

If the ultrasound shows that the lump is bigger than 1.0 centimeters, a special biopsy called a fine needle aspiration   (FNA) will be performed. This test determines if the lump is cancerous or benign.

Thyroid function tests are usually normal in patients with thyroid cancer.