Fine-Needle Aspiration and Core Needle Biopsy of Thyroid Nodules

Thyroid nodules are exceedingly common in older adults and are frequently asymptomatic and incidental, which in turn poses a diagnostic challenge. Ultrasound (US) is the imaging modality of choice for the evaluation of the thyroid gland and for the stratification of lesions according to risk of malignancy based on sonographic features. Suspicious lesions that meet the criteria for biopsy may undergo sampling with US-guided fine-needle aspiration, which allows for safe and accurate cytologic diagnosis with minimal patient discomfort. Core needle biopsy can serve as a complementary technique in selected cases of prior nondiagnostic or inconclusive fine-needle aspiration (FNA) cytology or in the setting of suspected thyroid lymphoma or other less common thyroid malignancies such as anaplastic and medullary tumors. Molecular studies can help to further stratify the likelihood of malignancy and can aid in subsequent treatment decisions.