The use of fine-needle aspiration biopsy under ultrasound guidance to assess the risk of malignancy in patients with a multinodular goiter

Purpose: Fine-needle aspiration biopsy (FNAB) is a commonly performed proce dure used in the evaluation of solitary thyroid nodules, in which the risk of malignancy is approximately 5% in most patients. Recently, the use of ul trasound (US) guidance in FNAB has been shown to enhance the diagnostic eff icacy of this procedure. However, the risk of malignancy in thyroid nodules occurring within a multinodular goiter (MNG) has not been completely clari fied, nor has the optimal means of investigating such nodules using FNAB. S ubjects and Methods: We performed a retrospective study of all patients see n over a 4-year period with a MNG that had one or more nodules who underwen t FNAB under US guidance. The results from the history and physical examina tion, thyroid function and antibody tests, radionuclide studies, thyroid so nogram, cytology of aspirated nodules, and surgical pathology were recorded and analyzed. Results: A total of 93 nodules were aspirated in 61 patients with MNG. Adequate material was obtained in 96% of aspirates on the first attempt. Sixty-seven aspirates in 44 patients yielded benign cytology and 2 2 aspirates in 15 patients yielded suspicious cytology. All patients with s uspicious cytology underwent thyroid surgery. Thyroid cancer was found in 5 of these nodules, including 4 cases of papillary cancer and 1 case of Hurt hle cell cancer, and 1 additional patient had occult papillary cancer disco vered. The overall malignancy rate in thyroid nodules among the patients wi th MNG was approximately 5%. Conclusions: FNAB under US guidance is a usefu l diagnostic modality in the evaluation of thyroid nodules in selected pati ents with MNG. Because the risk of thyroid malignancy in these nodules is c omparable to that which exists in solitary thyroid nodules, the possibility of thyroid malignancy should be considered in all patients with MNG.