Malignant thyroid teratoma (MTT) is a very rare thyroid malignancy. These neoplasms have been reported only in case reports and small-sized case series so far. In this study, we searched for MTTs in the Surveillance, Epidemiology, and End Result (SEER) program during 1975-2016. Subsequently, we incorporated the SEER data with published MTT cases in the literature to analyze the characteristics and prognostic factors of MTTs. Integrated data were analyzed using Chi-square or Fisher’s exact test for categorical covariates, and t-test or Mann-Whitney test for continuous variables. We included 28 studies with 36 MTT cases and found additional 8 cases from the SEER program for final analyses. Our results showed that MTT is typically seen in adult females. These neoplasms were associated with an aggressive clinical course with high rates of extrathyroidal extension (80%) and nodal involvement (62%). During follow-up, the development of recurrence and metastases were common (42% and 46%, respectively), and one-third of patients died at the last follow-up. Large tumor size (p = 0.022) and the presence of metastases during follow-up (p = 0.008) were associated with a higher mortality rate. In conclusion, our study demonstrated the characteristic features of MTT patients and outlined some parameters associated with a negative outcome which could help clinicians better predict the clinical course of these neoplasms.
Huy Gia Vuong, Truong P.x. Nguyen, Hanh T.t. Ngo, Lewis Hassell, and Kennichi Kakudo
Huy Gia Vuong, Toru Odate, Hanh T T Ngo, Thong Quang Pham, Thao T K Tran, Kunio Mochizuki, Tadao Nakazawa, Ryohei Katoh, and Tetsuo Kondo
There are ongoing debates with respect to the prognostic roles of molecular biomarkers in sporadic medullary thyroid carcinoma (MTC). In this study, we aimed at investigating the prognostic value of RET and RAS mutations – the two most common mutations in sporadic MTCs. A search was conducted in four electronic databases. Relevant data were extracted and pooled into odds ratios (OR), mean differences (MD) and corresponding 95% confidence intervals (CI) using the random-effect model. We used Egger’s regression test and visual of funnel plots to assess the publication bias. From 2581 studies, we included 23 studies with 964 MTCs for meta-analysis. Overall, the presence of RET mutation was associated with an elevated risk for lymph node metastasis (OR = 3.61; 95% CI = 2.33–5.60), distant metastasis (OR = 2.85; 95% CI = 1.64–4.94), advanced tumor stage (OR = 3.25; 95% CI = 2.02–5.25), tumor recurrence (OR = 3.01; 95% CI = 1.65–5.48) and patient mortality (OR = 2.43; 95% CI = 1.06–5.57). RAS mutation had no significant prognostic value in predicting tumor aggressiveness. To summarize, our results affirmed that RET mutation is a reliable molecular biomarker to identify a group of highly aggressive sporadic MTCs. It can help clinicians better assess patient prognosis and select appropriate treatment decisions.