A Brief Synopsis of AFP's "Thyroid Nodules"

Thyroid Nodules
MARK A. KNOX, MD, Hawaii Island Family Medicine Residency, Hilo, Hawaii
Am Fam Physician. 2013 Aug 1;88(3):193-196.
http://www.aafp.org/afp/2013/0801/p193.pdf

     Thyroid nodules are common findings on physical exam and imaging. They may present as a protrusion in the neck, even causing compressive symptom. Risk factors for cancer in these nodules are a history of neck irradiation, a family history of thyroid cancer (medullary of papillary), and possibly graves disease. The first step in the algorithm requires the physician to do a full history, exam, TSH, and ultrasound. If the TSH is low, a thyroid scan can be done to rule out a hyperfunctioning nodule. If it is hyperfunctioning, radioiodine ablation or surgical excision can be performed. The radioactive iodine does not harm surrounding tissue because of the healthy tissues' low uptake. If the TSH is normal or high, the size of the nodule determines the plan. Nodules 1 cm or smaller can be followed up clinically. Larger nodules can be aspirated by ultrasound guided FNA.
     Aspiration results are classified as malignant, suspicious, benign, or indeterminate/ nondiagnostic. Indeterminate/ nondiagnostic samples can be repeated within a month. If the findings are benign, the patient can be followed with an ultrasound in 6-18 months. If the nodule does not grow, then the follow up interval can be extended to 3-5 years, otherwise a repeat FNA can be done. Malignant or suspicious samples should be referred (the R word!) for surgery. Nodules larger than 4 cm usually require a lobectomy.
     Calcitonin levels can be checked in patients suspected of medullary thyroid cancer, although sufficient evidence for this practice is lacking.   Ethanol injection can be done to recurrent cystic nodules.
     Pregnant women will have higher rates of thyroid nodules, but the rate of cancer is unchanged. Nodules are rarer in children, but the rate of cancer is higher.