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Overview of thyroid nodule formation

Douglas S Ross, MD
Section Editor
David S Cooper, MD
Deputy Editor
Jean E Mulder, MD


This topic will review the prevalence, risk factors, risk of cancer, and etiology of thyroid nodules. An understanding of these factors is essential in developing a reasonable diagnostic approach to patients with these thyroid nodules. (See "Diagnostic approach to and treatment of thyroid nodules".)


Nodularity of thyroid tissue is extremely common. In a large population study (Framingham, MA), as an example, clinically apparent thyroid nodules were present in 6.4 percent of women and 1.5 percent of men [1]. These figures significantly underestimate the true frequency of this disorder, as evidenced by the following:

In surveys of unselected subjects using ultrasonography, 20 to 76 percent of women had at least one thyroid nodule [2,3]. In Germany, an area of relative iodine deficiency, 96,278 screening ultrasounds found thyroid nodules or goiter in 33 percent of men and 32 percent of women; nodules over 1 cm were found in 11.9 percent of the population [4].

The prevalence of nodular goiter increased with age from 2.7 and 2.0 percent in women and men aged 26 to 30 years, to 8.7 and 6.7 percent in women and men aged 36 to 40 years, to 14.1 and 12.4 percent in women and men aged 45 to 50 years, and to 18.0 and 14.5 percent in women and men over age 55 years [4].

In several autopsy surveys, 37 to 57 percent of patients had thyroid nodules [5,6].

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Literature review current through: Oct 2017. | This topic last updated: Jul 20, 2017.
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