Thyroid Nodules and Goiters:

MARIUS STAN, MD
VAHAB FATOURECHI, MD

Mayo Clinic College of Medicine

Dr Stan is an instructor in medicine at the Mayo Clinic College of Medicine in Rochester, Minn; he is also a fellow in endocrinology in the division of endocrinology, diabetes, metabolism, and nutrition at the Mayo Clinic in Rochester. Dr Fatourechi is professor of medicine in the division of endocrinology, diabetes, metabolism, and nutrition at the Mayo Clinic College of Medicine.

ABSTRACT: Malignancy must be ruled out in palpable as well as nonpalpable nodules larger than 1 cm. If the thyroid-stimulating hormone (TSH) level is normal or elevated, cytologic evaluation via fine-needle aspiration (FNA) is recommended if a nodule is identified. The use of ultrasound-guided FNA increases the diagnostic yield. About 5% to 10% of FNAs are nondiagnostic; this is more likely with smaller nodules and with palpation-guided FNA. Follow-up visits for benign nodules include clinical reassessment, TSH testing, and measurement of the nodule. Surgery is indicated for malignant nodules, large benign nodules, or symptomatic multinodular goiters. If the TSH level is subnormal, a radionuclide thyroid scan is recommended. Patients with "hot" nodules require evaluation and possible treatment for hyperthyroidism. Radioiodine therapy is safe and effective for these patients and for patients with toxic multinodular goiters (particularly those with small goiters and those with a history of thyroidectomy).

CLINICAL HIGHLIGHTS

In a patient with multiple nodules, the selection of the nodule to be aspirated is based on ultrasonographic characteristics likely to suggest malignancy, such as microcalcifications, solid hypoechoic appearance, increased vascularity, and irregular borders.
Follow-up visits for benign nodules are scheduled within 6 to 18 months. A repeated fine-needle aspiration (FNA) is warranted by changes in nodule texture, a persistently recurrent cyst, development of compressive symptoms, or nodule growth.
Thyroxine suppression therapy is generally not indicated in iodine-sufficient groups; only 20% of patients show nodule shrinkage, and the suppression of thyroxine and subclinical hyperthyroidism may have adverse effects on the cardiovascular system and bones.
Pathologic evaluation is unnecessary for "hot" nodules, because they are very rarely malignant. Surgery is indicated for patients with local compressive symptoms, those with glands larger than 100 g, and those who refuse radioactive iodine treatment.
The evaluation of thyroid incidentalomas larger than 1 cm is similar to that of palpable nodules of this size. For incidentalomas smaller than 1 cm, further evaluation, including FNA, is warranted if the history, physical examination, or ultrasonographic findings suggest malignancy.

Wiest PW, Hartshorne MF, Inskip PD, et al. Thyroid palpation versus high-resolution thyroid ultrasonography in the detection of nodules. J Ultrasound Med. 1998;17:487-496.
Zelmanovitz F, Genro S, Gross JL. Suppressive therapy with levothyroxine for solitary thyroid nodules: a double-blind controlled clinical study and cumulative meta-analyses. J Clin Endocrinol Metab. 1998;83:3881-3885.

AACE/AME Task Force on Thyroid Nodules. American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules. Endocr Pract. 2006; 12:63-102.
Cooper DS, Doherty GM, Haugen BR, et al. Management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2006;16: 109-142.
Frates MC, Benson CB, Charboneau JW, et al. Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement. Radiology. 2005;237:794-800.

REFERENCES:
1. Vander JB, Gaston EA, Dawber TR. The significance of nontoxic thyroid nodules. Final report of a 15-year study of the incidence of thyroid malignancy. Ann Intern Med. 1968;69:537-540.
2. Wiest PW, Hartshorne MF, Inskip PD, et al. Thyroid palpation versus high-resolution thyroid ultrasonography in the detection of nodules. J Ultrasound Med. 1998;17:487-496.
3. Mariotti S, Franceschi C, Cossarizza A, Pinchera A. The aging thyroid. Endocr Rev. 1995;16:686-715.
4. AACE/AME Task Force on Thyroid Nodules. American Association of Clinical Endocrinologists and Associazione Medici Endocrinologi medical guidelines for clinical practice for the diagnosis and management of thyroid nodules. Endocr Pract. 2006; 12:63-102.
5. Hagag P, Strauss S, Weiss M. Role of ultrasound-guided fine-needle aspiration biopsy in evaluation of nonpalpable thyroid nodules. Thyroid. 1998;8:989-995.
6. Cooper DS, Doherty GM, Haugen BR, et al. Management guidelines for patients with thyroid nodules and differentiated thyroid cancer. Thyroid. 2006;16:109-142.
7. Ortiz R, Hupart KH, DeFesi CR, Surks MI. Effect of early referral to an endocrinologist on efficiency and cost of evaluation and development of treatment plan in patients with thyroid nodules. J Clin Endocrinol Metab. 1998;83:3803-3807.
8. Frates MC, Benson CB, Charboneau JW, et al. Management of thyroid nodules detected at US: Society of Radiologists in Ultrasound consensus conference statement. Radiology. 2005;237:794-800.
9. Court-Payen M, Nygaard B, Horn T, et al. US-guided fine-needle aspiration biopsy of thyroid nodules. Acta Radiol. 2002;43:131-140.
10. Marqusee E, Benson CB, Frates MC, et al. Usefulness of ultrasonography in the management of nodular thyroid disease. Ann Intern Med. 2000; 133:696-700.
11. Kunreuther E, Orcutt J, Benson CB, et al. Prevalence and distribution of carcinoma in the uninodular and multinodular goiter. Presented at: 76th Annual Meeting of the American Thyroid Association; 2004; Vancouver, British Columbia.
12. Gharib H, Goellner JR, Johnson DA. Fine-needle aspiration cytology of the thyroid. A 12-year experience with 11,000 biopsies. Clin Lab Med. 1993; 13:699-709.
13. Thyroid Carcinoma Task Force. AACE/AAES medical/surgical guidelines for clinical practice: management of thyroid carcinoma. American Association of Clinical Endocrinologists. American College of Endocrinology. Endocr Pract. 2001;7:202-220.
14. Gharib H, Goellner JR. Fine-needle aspiration biopsy of the thyroid: an appraisal. Ann Intern Med. 1993;118:282-289.
15. Alexander EK, Heering JP, Benson CB, et al. Assessment of nondiagnostic ultrasound-guided fine needle aspirations of thyroid nodules. J Clin Endocrinol Metab. 2002;87:4924-4927.
16. Ylagan LR, Farkas T, Dehner LP. Fine needle aspiration of the thyroid: a cytohistologic correlation and study of discrepant cases. Thyroid. 2004;14:35-41.
17. Carmeci C, Jeffrey RB, McDougall IR, et al. Ultrasound-guided fine-needle aspiration biopsy of thyroid masses. Thyroid. 1998;8:283-289.
18. Bennedbaek FN, Perrild H, Hegedus L. Diagnosis and treatment of the solitary thyroid nodule. Results of a European survey. Clin Endocrinol (Oxf). 1999;50:357-363.
19. Papini E, Petrucci L, Guglielmi R, et al. Long-term changes in nodular goiter: a 5-year prospective randomized trial of levothyroxine suppressive therapy for benign cold thyroid nodules. J Clin Endocrinol Metab. 1998;83:780-783.
20. Castro MR, Caraballo PJ, Morris JC. Effectiveness of thyroid hormone suppressive therapy in benign solitary thyroid nodules: a meta-analysis. J Clin Endocrinol Metab. 2002;87:4154-4159.
21. Zelmanovitz F, Genro S, Gross JL. Suppressive therapy with levothyroxine for solitary thyroid nodules: a double-blind controlled clinical study and cumulative meta-analyses. J Clin Endocrinol Metab. 1998;83:3881-3885.
22.Gharib H, Mazzaferri EL. Thyroxine suppressive therapy in patients with nodular thyroid disease. Ann Intern Med. 1998;128:386-394.
23. Hegedus L, Bonnema SJ, Bennedbaek FN. Management of simple nodular goiter: current status and future perspectives. Endocr Rev. 2003;24: 102-132.
24.Nelson RL, Wahner HW, Gorman CA. Rectilinear thyroid scanning as a predictor of malignancy. Ann Intern Med. 1978;88:41-44.
25. Kang KW, Kim SK, Kang HS, et al. Prevalence and risk of cancer of focal thyroid incidentaloma identified by 18F-fluorodeoxyglucose positron emission tomography for metastasis evaluation and cancer screening in healthy subjects. J Clin Endocrinol Metab. 2003;88:4100-4104.