Abstract
Medullary thyroid carcinoma (MTC) accounts for only 2-5% of all thyroid malignancies. Clinical and pathological characteristics alone may suffice to predict outcomes, but unstable behavior in some cases suggests that other factors may influence a worse course of the disease. This study aims to identify criteria that could predict increased aggressiveness. We analyzed 59 consecutive MTC cases. We focused on the relationships among clinicopathological characteristics, parameters of aggressiveness (extrathyroidal extension, lymphovascular invasion, and lymph node metastasis), and parameters for MTC grading. Statistically significant correlations were found for tumor size, lymphovascular invasion, and lymph node metastasis and tumor focality and lymph node metastasis. Our results showed, in tumors larger than 40 mm, odds ratios (ODs) of 13.695 and 6 for lymphovascular invasion and lymph node metastasis, respectively; in multifocal tumors, we registered an OD of 9.42 for lymph node metastasis. No significant correlation was found for the parameters of the MTC grading system when assessed individually and integrated by reporting low-grade and high-grade risk groups. Although our data indicate that lymphovascular invasion and lymph node metastasis remain significant markers for aggressiveness, studies on larger series of cases are mandatory to detect and validate new factors responsible for the variable course of MTC.