Papillary Thyroid Microcarcinoma (PTMC): Ultrasonographic Characteristics Correlated With Pathological Findings

ABSTRACTObjective: To study the ultrasonographic features and pathological findings of papillary microcarcinoma of the thyroid (PTMC).Materials and Methods: The clinical data of thyroid lesions which measured lcm or less in maximal diameter were retrospectively analyzed, including 47 cases with PTMC (51 nodules) and 112 cases with benign thyroid lesions (118 nodules). All patients had been performed with thyroid ultrasonography preoperatively, and whose thyroid tissues were pathologically analyzed afterwards. The sensitivity and specificity of ultrasonographic examinations were then calculated.Results: There was no correlation between solitary and multiple thyroid nodules of thyroid gland and the incidence of PTMC. The common ultrasonographic features of PTMC included irregular shape (60.78%), ill defined margins (70.59%), absent halo sign (96.08%), hypoechoic texture (94.12%), heterogeneous texture (78.43%), solid (100%), microcalcifications (58.82%), metastatic lymph nodes (43.14%) and internal blood flow pattern (68.63%). With ultrasonographic characteristics, statistical significance (P＜0.05) was noted between benign and malignant micro-nodules of thyroid. The sensitivities and specificities of the ultrasonographic characteristics of PTMC were irregular shape(60.8%, 93.2%), ill defined margins(70.6%, 89.0%), absent halo sign(96.1%, 15.3%), hypoechoic texture(94.1%, 30.8%), heterogeneous texture(78.4%, 37.3%), solid (100%, 54.2%), microcalcifications (58.8%, 96.6%), metastatic lymph nodes (43.1%, 97.5%) and internal blood flow pattern (68.6%, 88.1%). With all the ultrasonographic features mentioned above, the sensitivity and specificity of the ultrasonography in diagnosing PTMC is 98.0% and 89.0%, respectively. Histopathologically, the PTMC are often small grey-white lesions (lcm or less in diameter), representing with a pure papillary or a papillary with follicular patterns, with intratumoural sclerosis sometimes. And usually, the proportion of above-mentioned tumor components is various.Conclusion: Ultrasonography is very useful in diagnosing PTMC. The ultrasonographic characteristics of PTMC accord with the pathologic changes.