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.

中文翻译：

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恶性甲状腺畸胎瘤：病例系列/病例报告的综合分析。

恶性甲状腺畸胎瘤（MTT）是一种非常罕见的甲状腺恶性肿瘤。迄今为止，仅在病例报告和小型病例系列中报告了这些肿瘤。在这项研究中，我们在 1975-2016 年期间在监测、流行病学和最终结果 (SEER) 计划中搜索了 MTT。随后，我们将 SEER 数据与文献中已发表的 MTT 病例相结合，以分析 MTT 的特征和预后因素。对分类协变量使用卡方或 Fisher 精确检验，对连续变量使用 t 检验或 Mann-Whitney 检验分析综合数据。我们纳入了 28 项研究，其中 36 例 MTT 病例，并从 SEER 计划中发现了另外 8 例用于最终分析的病例。我们的研究结果表明，MTT 通常见于成年女性。这些肿瘤与侵袭性临床病程相关，甲状腺外扩展率高（80%）和淋巴结受累率高（62%）。在随访期间，复发和转移的发展很常见（分别为 42% 和 46%），三分之一的患者在最后一次随访时死亡。大肿瘤（P = 0.022）和随访期间存在转移（P = 0.008）与较高的死亡率相关。总之，我们的研究证明了 MTT 患者的特征，并概述了与阴性结果相关的一些参数，这些参数可以帮助临床医生更好地预测这些肿瘤的临床过程。三分之一的患者在最后一次随访中死亡。大肿瘤（P = 0.022）和随访期间存在转移（P = 0.008）与较高的死亡率相关。总之，我们的研究证明了 MTT 患者的特征，并概述了与阴性结果相关的一些参数，这些参数可以帮助临床医生更好地预测这些肿瘤的临床过程。三分之一的患者在最后一次随访中死亡。大肿瘤（P = 0.022）和随访期间存在转移（P = 0.008）与较高的死亡率相关。总之，我们的研究证明了 MTT 患者的特征，并概述了与阴性结果相关的一些参数，这些参数可以帮助临床医生更好地预测这些肿瘤的临床过程。