In the general population, the prevalence of thyroid nodules varies from 4% by palpation to 67% by ultrasonagraphy.1,2 A prevalence of 50% has been reported on autopsy data from patients with no history of thyroid disease.1 Thyroid incidentalomas are noted in approximately 40% of patients undergoing an examination for suspected parathyroid disease and in 13% of patients undergoing carotid ultrasonography.1

The prevalence of thyroid nodules increases with age. Six to ten percent of older patients have solitary nodules; goiters and multinodular glands tend to be more common in the elderly.3 A prospective study examining the prevalence of thyroid nodules in asymptomatic North American subjects showed a tendency toward an increased probability of thyroid nodules with increasing age, with peak frequencies identified in those aged 48 to 50 and 56 to 60 years, but the relationship between age and an abnormal thyroid ultrasound was not statistically significant.2 In a recent survey, the prevalence of goiter in the elderly population in a mildly to moderately iodine deficient area was 74% in patients aged 55-75 years and 54% in patients aged 76-84 years. The prevalence of nodular goiter in these groups was 25% and 21%, respectively.4

In the older patient population, hyperfunctional nodules may result in T3 toxicosis characterized by thyrotoxicosis associated with an elevated T3 concentration and a normal T4 concentration. A cross-sectional study that included 634 patients with a mean age of 67 years in Spain reported nontoxic multinodular goiter (51.3%) as the most common cause of a goiter, followed by toxic multinodular goiter (23.8%).5 Other causes of a goiter in this study were: solitary thyroid nodule (9.8%), toxic adenoma (5%), Graves’ disease (4.3%), Hashimoto’s thyroiditis (3.9%), simple goiter (1.3%), and thyroiditis (0.5%). In an older study from the Mayo Clinic, 60% of patients over the age of 60 with multinodular goiter were reported to be thyrotoxic.6

Thyroid nodules can represent benign adenomas, cancer, cysts, or inflammation. The approach to a solitary nodule in an older individual is the same as that in a younger patient. The first step should be measurement of serum TSH. If the TSH is suppressed and a radioiodine scan shows increased uptake in the nodule, it is hyperfunctional, and further workup for thyroid cancer is unnecessary. However, if the thyroid function tests are normal, fine needle aspiration (FNA) of the nodule should be performed to make a specific diagnosis. For a complete discussion on the evaluation and management of thyroid nodules, please refer to Chapter 18, and for evaluation and management of multinodular goiter, please refer to Chapter 17.