Significance of high frequency ultrasonography in detecting medullary thyroid carcinoma

Objective: To evaluate the significance of ultrasonography in diagnosis of medullary thyroid carcinoma. Methods: The ultrasonographic features were analyzed in 25 nodules of medullary thyroid carcinoma proved by pathologic examination after operation during September 2005 to September 2010, and data of ultrasonography in 126 nodules of papillary thyroid carcinoma in the same period were also analyzed. Each nodule was evaluated as suspicious malignant, indeterminate or probably benign. The findings of medullary and papillary carcinomas were compared using the chi-squared test. Results: The position, internal content, margin, echogenicity, calcification and cervical lymph node on ultrasound imaging were not different significantly (P=0.564, P=0.749, P=0.126, P=0.268, P=0.190, P=0.786). The US findings for MTCs were in middle and upper pole of thyroid (68%), solid internal content (91%), ovoid or round shape (56%), spiculated or ill-defined margin (80%), marked hypo echogenicity (52%) and calcifications (52%). Among the 25 nodules of MTC, 20 nodules (80%) were classified as suspicious malignant nodules. The mean size (longest diameter) of MTC lesions was 20 ± 12.7 mm and the mean size (longest diameter) of PTC lesions was 12 ± 5.5 mm. This difference was statistically significant (P<0.05). Ovoid or round shape was more prevalent in MTC nodules than in PTC nodules (P<0.05). Conclusion: The sonographic findings of MTC were similar to the other thyroid malignancy and had their own characteristics. Ultrasonography can provide valuable information for early diagnosis and surgical treatment of these patients. (authors)