Comparison of Ultrasound, Pathologic and Prognostic Characteristics of the Follicular Variant of Papillary Thyroid Cancer According to Fine-Needle Aspiration Cytology.

The aim of the study described here was to compare ultrasound features, pathologic characteristics and prognoses of the follicular variant of papillary thyroid carcinoma (FVPTC) according to cytology results. Eighty-seven FVPTCs were classified according to the first cytology results as the surgery group (n = 66, follicular neoplasm/Hürthle cell neoplasm, suspicious for malignancy and malignancy) and the indeterminate group (n = 21, non-diagnostic and benign), for whom the management was follow-up. The indeterminate group had a longer mean interval to surgery (p = 0.020) and larger tumor size (p = 0.018). More tumors were assessed as probably benign in the indeterminate group than in the surgery group (p < 0.001). Extrathyroidal extension and lymph node metastasis did not significantly differ between the two groups, and no patient had a recurrence (mean follow-up interval: 54.9 ± 16.9 mo). The indeterminate group exhibited more probably benign features and larger size on ultrasound, with surgery being performed at a later date. However, aggressive pathologic characteristics and tumor recurrence did not significantly differ between the two groups.