RESUMEN
Ultrasonography (US) is the preferred imaging modality for papillary thyroid microcarcinoma (PTMC). The aim of this study was to evaluate the importance of gray-scale ultrasound combined with elastography to predict extrathyroidal extension and cervical lymph node (LN) metastasis in patients with PTMC. We retrospectively evaluated gray-scale ultrasonic and elastographic results from 119 consecutive cases of PTMC with 138 nodules and correlated the histopathological findings. The results indicated that pathological extrathyroidal extension was significantly associated with T staging on US, extrathyroidal extension on US, bilaterality on US, boundary, strain ratio and hard malignancy as measured with the Rago score. Central LN metastasis on pathology was significantly associated with central LN metastasis on US, lateral LN metastasis on US, multifocality on US and bilaterality on US. Lateral LN metastasis on US was significantly associated with lateral LN metastasis on pathology. On multivariate analysis, T staging on US, extrathyroidal extension on US and hard malignancy as measured with the Rago score were significantly associated with pathological extrathyroidal extension. Lateral LN metastasis on US and bilaterality on US were independent factors in predicting central LN metastasis on pathology. Lateral LN metastasis on US was the predictive factor for lateral LN metastasis on pathology. US should be helpful in the diagnosis of PTMC and in the evaluation of possible PTMC recurrence on US in routine clinical practice.