Diagnostic value of ultrasound-guided fine needle aspiration biopsy in malignant thyroid nodules: utility for micronodules.

BACKGROUND The diagnostic approach to thyroid nodules involves ultrasound-guided fine needle aspiration biopsy (US-FNAB).We especially aimed to evaluate the contribution and the place of US-FNAB in preoperative evaluation of the malignant cases and draw attention to discordant cases diagnosed with papillary thyroid microcarcinoma (PTMC). MATERIALS AND METHODS A total of 276 cases were retrospectively reviewed who were subsequently diagnosed with a malignancy and who underwent US-FNAB. RESULTS Some 45 were found to have previously undergone the US-FNAB procedure. Of the patients in whom the surgical specimen was diagnosed with a malignancy, 21 (46.7%) were diagnosed as malignant or suspicious for malignancy, and 24 (53.3%) were concluded as benign or insufficient for diagnosis. Patients with the diagnosis of PTMC outnumbering the others was a striking finding (11 cases, 24%). CONCLUSIONS We suggest performing repeat aspiration biopsy considering sampling errors in cases where inconsistency exists between clinical findings and cytological results in thyroid nodules smaller than 10 mm in diameter and with suspicious findings on ultrasonography.