Does a Thyroid Imaging Reporting and Data System (TI-RADS) 4 lesion with multiple nodules greater than 1.5 cm in size, thyromegaly, and a thyroid goiter require a biopsy?

From the Guidelines

A biopsy is likely recommended but not definitively required at this point, given the TI-RADS 4 classification and the radiologist's recommendation for follow-up ultrasound. The TI-RADS 4 classification indicates a moderately suspicious nodule, which typically has a 15-20% risk of malignancy 1. While many TI-RADS 4 nodules do warrant fine needle aspiration (FNA) biopsy, the radiologist has specifically recommended follow-up ultrasound rather than immediate biopsy. This suggests they want to monitor the nodules over time before deciding on more invasive procedures. Some key points to consider include:

• The presence of multiple similar-appearing nodules in a goiter (enlarged thyroid) often indicates a multinodular goiter, which is commonly benign 1.
• Fine needle aspiration cytology (FNAC) is an important technique that is used along with US for the diagnosis of thyroid nodules, and should be performed in any thyroid nodule >1 cm and in those <1 cm if there is any clinical or ultrasonographic suspicion of malignancy 1.
• The use of various immunohistochemical markers in cytologic samples to differentiate papillary thyroid carcinoma from other follicular-derived lesions of thyroid has been explored, but none of the markers appears to be specific enough to be employed as the diagnostic marker for the cytologic diagnosis of papillary thyroid carcinoma 1. However, you should discuss these results with your endocrinologist or primary care physician promptly, as they may recommend biopsy based on additional factors such as your medical history, risk factors, nodule size, and any concerning symptoms. The final decision about biopsy timing should be made in consultation with your doctor who can evaluate your complete clinical picture, taking into account the latest guidelines for diagnosis, treatment and follow-up of thyroid cancer 1.

From the Research

Thyroid Nodule Evaluation

The provided thyroid impression indicates a TI-RADS 4, moderately suspicious nodule, with multiple similar-appearing nodules greater than 1.5 cm in size, thyromegaly, and the appearance of a thyroid goiter.

Biopsy Recommendation

• The study by 2 highlights the importance of fine-needle aspiration biopsy (FNAB) in evaluating thyroid nodules with suspicious clinical findings or ultrasound features suggestive of malignancy.
• Another study by 3 discusses the limitations of FNA, including a substantial rate of inconclusive results and indeterminate interpretations, and proposes core needle biopsy (CNB) as a complementary or alternate diagnostic method.
• The study by 4 evaluates the effectiveness of FNAB in the diagnosis of thyroid cancer and thyroid disease, and found that FNAB has become a useful procedure in the study and diagnosis of thyroid diseases.
• The American Thyroid Association (ATA) guidelines, as mentioned in the study by 5, suggest that FNAB is recommended for nodules with suspicious ultrasound features, which is consistent with the provided thyroid impression.
• The study by 6 emphasizes the importance of fine-needle aspiration biopsy as the gold standard for malignancy diagnosis in thyroid cancer.

Diagnostic Performance

• The diagnostic performance of US-based FNAB criteria varies according to individual international society guidelines, as shown in the study by 5.
• The study by 5 also found that the rate of unnecessary FNAB was lowest with the American College of Radiology (ACR) guidelines, followed by the French Society of Endocrinology (FSE) guidelines.

Follow-up Ultrasound

• The provided thyroid impression recommends follow-up ultrasound, which is consistent with the study by 6 that discusses the importance of surveillance ultrasound in papillary microcarcinomas.