FNAB in thyroid nodules

Ally Prebtani, MD, is a professor of medicine in the Division of Endocrinology and Metabolism at McMaster University.

Does every thyroid nodule require a fine-needle aspiration biopsy as the next diagnostic step?

Most thyroid nodules probably don’t need a biopsy, but it is really important to get a biopsy on the high-risk nodules. This is based on clinical factors such as being of young age, male gender, the size of the nodule. Are there any lymph nodes? Is there a family history? Was there a history of radiation exposure?

That being said, those are very, very important, but probably one of the most important reasons when a patient needs a fine-needle aspiration biopsy of the nodule is based on the ultrasonographic criteria of something called the Thyroid Imaging Reporting and Data System (TI-RADS). TI-RADS is a classification system used to determine the risk of the malignancy. It’s not only based on size, but it’s based on the shape of the nodule. Are there any lymph nodes? It’s also based on the echogenicity of the nodule—whether it’s solid or cystic—and also whether there are any calcifications, and the margins.

We use all these characteristics and there’s a score given, and the higher the TI-RADS score, the more risky it is that it is malignant. At that time you will decide to do a biopsy based on the history, physical [examination], but, more importantly, the TI-RADS classification based on ultrasonography of these nodules.