A nodule forms as a small lump, or localized growth, in an otherwise normal thyroid gland. It differs from a goiter, which is an enlarged thyroid gland. Although 90 to 95 percent of all nodules are benign (noncancerous), a physician should fully test all nodules to ensure that a malignant (cancerous) growth is not present. When nodules form within the gland, the area appears to be raised.
Nodules are very common. The growths may be fluid-filled (cysts), consist of solid thyroid tissue (hyperactive nodule), or comprise many growths (multinodular goiter). Nodules range in size; some measure less than a millimeter, others may be as large as a few inches. A nodule is not a disease; rather it signals an underlying problem in the thyroid gland. Thus, determining whether the nodule is cancerous becomes a physician’s primary concern. A physician uses tests such as a thyroid ultrasound, a thyroid function test, a thyroid scan, and fine-needle-aspiration (FNA) biopsy to diagnose thyroid disease.
An estimated 50 percent of the population will develop small nodules at some time. Most nodules go unnoticed, and only four to seven percent of the population will develop a nodule that is large enough for a physician to detect through throat palpitation (performed by feeling the throat).
If your physician suspects nodules or an underlying problem in the thyroid gland, you will probably be given an ultrasensitive thyroid-stimulating-hormone (TSH) test and a blood sample drawn. The physician sends it to a laboratory to determine if your TSH levels are high, low, or normal.