ABSTRACT
PURPOSE: Follicular neoplasms (FNs) such as follicular adenoma and carcinoma (FTC), nodular hyperplasia (NH) and follicular variant of papillary carcinoma (FVPC) share cytological features. In the present study, we investigate whether review of sonographic findings in patients with thyroid nodules suspicious of FN spares diagnostic thyroidectomies (DTs) by excluding benign diseases such as NH or not. METHODS: From June 1999 to May 2007, DTs were performed on 98 patients who had nodules suspicious of FN. High resolution sonographic findings are available for 53 patients. According to the final histologic diagnosis: Group I (23 patients) consisted of 20 FNs (11 FTCs), 1 Hurthle cell adenoma, 2 FVPC; Group II (30 patients) consisted of all others (23 NHs, 4 Hashimoto's thyroiditis, 3 papillary carcinomas (PTCs). Sonographic features were compared between the two groups. RESULTS: Three differential sonographic findings (DSF) i.e. irregular margin, absence of peripheral halo or marked inhomogeniety were identified more often in Group II than Group I (P<0.05). If we spared DTs for patients who have at least one DSF, 18 patients (34.0%) would have been selected for clinical follow-up whose final diagnoses were 14 NHs and 4 PTCs (including 1 FVPC). Sparing DTs by DSFs shows sensitivity, 56.7%; specificity, 95.7%; positive predictive value, 94.4%; negative predictive value, 62.9%; and accuracy, 73.6%, respectively. CONCLUSION: In patients with thyroid nodules suspicious of FN, sonographic findings such as irregular margin, absence of peripheral halo or marked inhomogeneity might spare DTs with the help of other diagnostic modalities such as cytogenetic or immunohistochemical studies.