We report a case of a 22-year-old female patient who was diagnosed with a cribriform-morular variant of papillary thyroid carcinoma (CMV-PTC). While at early ages this thyroid cancer variant is highly suggestive for familial adenomatous polyposis (FAP), there was no family history of FAP. In the tumor biallelic, inactivating APC variants were identified. The patient tested negative for germline variants based on analysis of genomic DNA from peripheral blood leukocytes. Somatic mosaicism was excluded by subsequent deep sequencing of leukocyte and normal thyroid DNA using next generation sequencing (NGS). This report presents a rare sporadic case of CMV-PTC, and to the best of our knowledge the first featuring two somatic APC mutations underlying the disease, with an overview of CMV-PTC cases with detected APC and CTNNB1 pathogenic variants from the literature.

中文翻译：

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乳头状甲状腺癌的早发性筛状-纹状体变异中两个体细胞APC突变的独特病例和文献综述。

我们报告了一例22岁的女性患者，该患者被诊断患有甲状腺乳头状癌的筛状-筛状变体（CMV-PTC）。虽然这种甲状腺癌变体在早期很可能提示家族性腺瘤性息肉病（FAP），但没有FAP家族史。在肿瘤双等位基因中，鉴定出失活的APC变体。根据对来自外周血白细胞的基因组DNA的分析，该患者的种系变异测试为阴性。随后通过下一代测序（NGS）对白细胞和正常甲状腺DNA进行深度测序，排除了体细胞镶嵌症。本报告介绍了一种罕见的CMV-PTC散发病例，据我们所知，第一个具有两个体细胞APC该疾病的潜在突变，并结合文献中检测到的AMV和CTNNB1致病变异的CMV-PTC病例进行概述。