Preoperative Diagnosis of Benign Thyroid Nodules with Indeterminate Cytology

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 . . .