Background: Thyroidectomy has been advocated for cystic nodules that recur after 2 fine-needle aspiration biopsies (FNABs) because of concern for malignancy.
Methods: A review of patients with nodular thyroid disease was completed to determine the frequency of cystic nodules, significance of the color and volume of aspirated fluid, frequency and factors predictive of cyst resolution, and incidence of carcinoma in cystic nodules.
Results: Thyroid nodules were cystic in 70 (18%) of 389 patients. FNAB was diagnostic in 50 (71%) patients with no false-negative results. Cyst resolution occurred in 10 (14%) patients. The mean volume of fluid aspirated from cysts that resolved was 14 +/- 12 mL compared with 8 +/- 18 mL from recurrent cysts (P > .05). Thyroidectomy was performed in 28 (40%) patients because of an abnormal or persistently nondiagnostic FNAB or compressive symptoms. Six patients (8.6%) had cancer, with a mean nodule size of 3.8 +/- 2.3 cm compared with 3.7 +/- 2.6 cm in patients with benign cysts (P > .05). Hemorrhagic fluid was aspirated in 4 patients with and 36 without cancer (P > .05).
Conclusions: FNAB of cystic thyroid nodules is rarely therapeutic and is a common cause of nondiagnostic rather than false-negative results. Recommendations for thyroidectomy should be based on FNAB rather than on size, fluid color, or failure of cyst resolution alone.