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Click here to view next page of this article Solitary Thyroid NoduleSolitary thyroid nodule (STN) affects between 4 and 8 percent of the general population, and its prevalence increases with age. Most STNs are found during routine medical evaluation. The vast majority of STNs are benign and, most frequently, colloid nodules. Thyroid cancer is present in 5 to 30 percent of palpable thyroid nodules. The significance of asymptomatic STN is debatable. Autopsy reports have shown a 50 percent incidence of asymptomatic thyroid nodule in patients over age 50 and a 60 percent incidence in patients over age 70. The incidence of occult thyroid carcinoma in autopsy specimens is about 10 percent. In this case, the physician's objective is to determine whether the recently discovered asymptomatic STN has a significant malignancy potential. A detailed medical history and targeted physical examination are important to uncover risk factors for thyroid cancer (Table 23). Age and Gender. Palpable nodular disease is more common in women than men and is most likely to be discovered in patients between ages 21 and 40.s4'sS,59 The incidence of carcinoma found in STN is greater in men than women. STN occurring at extremes of age is more likely to be cancerous. In children, STN is malignant in 30 to 50 percent of cases.,6E The incidence of carcinoma in patients with STN who are over age 50 increases progressively. STN in a man over age 50 is much more likely to be malignant than STN in a woman of the same age. The patient in Case 8 is 40 years old; both benign and malignant thyroid diseases occur. Family History. Patients with familial colonic polyposis (Gardener's syndrome) and familial goiter and hamartomas (Cowden's syndrome) have an increased risk for developing thyroid cancer and, thus, an increased probability that any nodule represents thyroid cancer.~ An increased incidence of thyroid cancer has also been reported in families with histories of breast, renal, or central nervous syndrome malignancy.~ In addition, women with a personal history of breast cancer are at increased risk for developing thyroid cancer. Cancer can metastasize to the thyroid gland and present as a palpable nodule. Medullary thyroid carcinoma (MTC) is frequently seen in families with a history of thyroid cancer. In these families, MTC occurs alone or as a component of multiple endocrine neoplasia (MEN) in association with either pheochromocytoma and hyperparathyroidism (MEN-2A) or pheochromocytomas and mucosal neuromas (MEN-2B). Thus, a family or personal medical history of long-standing constipation, diarrhea, pheochromocytoma, hyperparathyroidism, hypertension, or episodes of flushing or nervousness should arouse suspicion. Table 23 Risk of Cancer in Thyroid Nodule High risk Medical history History of radiation Multiple endocrine neoplasia type 2 Cowden's syndrome Familial polyposis Hoarseness Rapid growth, recent change in size Solitary nodule Male gender Younger or older age group Recurrent cystic nodule Compressive symptoms Nodules refractory to suppression Suspicious fine-needle aspiration biopsy results Physical examination Vocal cord paralysis Cervical lymphadenopathy Fixation to adjacent tissues or laryngotracheal complex Hard, nontender nodule Horner's syndrome Superior vena cava syndrome Nodules larger than 4 cm Distant metastases Low risk Medical history Family history of benign goiter Slow-growing or stable nodule Symptoms of hyper- or hypothyroidism Physical examination Multinodular goiter with no dominant nodule Tenderness or inflammatory changes Soft, cystic mass |