Which nodules should be biopsied in a multinodular goiter?

I saw a 46-year-old woman for second opinion regarding a multinodular goiter. She had several nodules over 1 cm in size. A dominant left-sided 2.2-cm heterogeneous nodule was biopsied by fine needle aspiration two years before with a “benign” result.

However, the cytopathology report stated the following: “No evidence of malignancy, interpretation limited by minimal number of follicular epithelial cells.” Thus, this appeared to be a non-diagnostic rather than a truly benign, fine needle aspiration result.

I repeated the thyroid ultrasound and noted a few nodules over 1 cm in size. The left 2.2-cm nodule was unchanged. However, immediately adjacent to it was a 0.9-cm hypoechoic nodule not reported in any of the previous ultrasound reports. It contained microcalcifications which raised suspicion of malignancy. On the right was a 1.4-cm hypoechoic nodule.

The patient agreed to have all three nodules biopsied by fine needle aspiration under ultrasound guidance in our office. We always have a cytotechnologist present to make up the slides and review for adequacy. If cellularity is insufficient, we obtain additional specimens until it is or until we and/or the patient decide it is time to stop. By following this practice, only rarely have we had non-diagnostic fine needle aspirations.

The 2.2-cm left and the 1.4-cm right nodules were benign. However, the 0.9-cm left nodule was suspicious for papillary cancer. The patient was sent for surgery which confirmed multifocal papillary thyroid cancer.

The standard practice for many years was for patients with multinodular goiter to have only the largest or most “dominant” nodule biopsied. More recently, research has suggested that nodules be selected not only by size but also based on other ultrasonographic features. Frates and colleagues* found that in patients with a multinodular goiter with three or more nodules greater than 1 cm in size but in whom only the largest was biopsied, almost 50% of thyroid cancer may be missed. They suggested that in patients with multiple nodules greater than 1 cm in size, up to a total of four be considered for biopsy.

In some communities, it is not the endocrinologist who performs the fine needle aspiration biopsy. I have heard that occasionally some radiologists have refused to biopsy non-dominant thyroid nodules despite the recommendations of the endocrinologist.

For those of you who have an interest in thyroid disorders but who are not already performing diagnostic ultrasound and ultrasound-guided fine needle aspiration, I strongly encourage you to consider doing so. Thyroid ultrasonography can become a rewarding part of your practice. Patients appreciate “one-stop shopping” and having the findings explained to them immediately by an expert instead of waiting to hear what the imaging study revealed. There are courses for those who would like to learn or improve their skills. A new endocrine certification in neck ultrasound is also available.

*J Clin Endocrinol Metab. 2006;91:3411–3417.