Preoperative Diagnosis of Benign Thyroid Nodules with Indeterminate Cytology

A significant fraction of fine-needle aspirates obtained from thyroid nodules are read as indeterminate. A new molecular test accurately predicts whether a cytologically indeterminate nodule is benign 93% of the time, permitting a conservative approach to management. Thyroid nodules are common and are usually benign. 1 However, 5 to 15% prove to be malignant; accordingly, identification of a nodule 1 cm or larger in diameter often prompts a diagnostic evaluation. 2 , 3 The cornerstone of thyroid-nodule evaluation is fine-needle aspiration, 4 which enables the assessment of cellular morphologic features that could not be identified by means of clinical assessment or imaging. Preoperative, ultrasonographically guided fine-needle aspiration has been shown to accurately classify 62 to 85% of thyroid nodules as benign, thereby avoiding diagnostic surgery. 5 However, 15 to 30% of aspirations yield indeterminate cytologic findings, 4 which include three subtypes: “atypia (or . . .