Clinical and ultrasonographic features of medullary thyroid microcarcinomas compared with papillary thyroid microcarcinomas: a retrospective analysis

Abstract

Background: To identify the sonographic features that help differentiate medullary thyroid microcarcinomas (MTMCs) smaller than 10 mm and papillary thyroid microcarcinomas (PTMCs). Methods: This study included 41 patients with 46 MTMCs and 104 consecutive patients with 136 PTMCs. All the nodules were surgically and histologically proved. The age and nodule size were analyzed by independent sample t test, and the gender, multiplicity and cervical lymph node metastases were analyzed by χ 2 or Fisher’s exact tests. Univariate analysis and multivariate logistic regression analysis were performed on the sonographic features of thyroid nodules, including location, shape, boundary, margin, peripheral halo ring, echogenicity, composition, calcifications and vascularization. Results: Compared with PTMCs, there were more MTMCs patients with cervical lymph node metastases (P=0.040). There were no significant differences in age, gender, nodule size, multiplicity, location, boundary, margin, peripheral halo ring, echogenicity and microcalcification between MTMCs and PTMCs (P < 0.05 for all). However, significant differences were found in shape (P=0.000), composition (P=0.032), macrocalcification (P=0.004) and vascularity (P=0.000) between the two groups. Conclusions: MTMCs had some overlapping sonographic features with PTMCs, however, MTMCs were more likely to be >50% solid composition, ovoid to round nodules with macrocalcifications and hypervascularity, and cervical lymph node metastases were more common in MTMCs patients.