Medullary thyroid carcinoma is a malignant uncommon and aggressive tumour of the parafollicular C cells. In about 75% of cases it is sporadic while, in case of RET mutation, it is associated to multiple endocrine neoplasia type 2 (25% of cases). The biochemical features of medullary thyroid carcinoma include the production of calcitonin and carcinoembryogenic antigen. The above-mentioned features are useful in the diagnostic process as well as in the follow up and in the prognostication of the disease. Even if calcitonin elevation is strongly associated to MTC, it can also be found increased in many pathological different conditions as pregnancy, lactation, C-cells hyperplasia, autoimmune thyroiditis, end stage renal disease, lung and prostate cancer and several neuroendocrine tumours. Major medullary thyroid tumours are usually connected to high doses of circulating calcitonin, in fact non-secretory variants have hardly been described. We herein report the case of a 59 years old male, who had undergone total thyroidectomy for multinodular goiter with negative preoperative calcitonin, showing medullary thyroid carcinoma at definitive pathology. To the best of our knowledge, this is the first case documenting a non-secretory medullary thyroid carcinoma, with double negative markers at the time of diagnosis and at the relapse. A Literature review underlining pathological hypothesis, differential diagnosis and alternative and innovative biomarkers to identify non-secretory medullary thyroid carcinoma was carried out.

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降钙素和CEA双阴性的甲状腺髓样癌：一例病例报告并文献复习更新

甲状腺髓样癌是滤泡旁C细胞的恶性罕见和侵袭性肿瘤。在约75％的病例中，它是散发的，而在RET突变的情况下，它与2型多发性内分泌瘤形成相关（25％的病例）。甲状腺髓样癌的生化特征包括降钙素和致癌胚抗原的产生。上述特征在诊断过程中以及在疾病的随访和预后中是有用的。即使降钙素升高与MTC密切相关，也可以在许多病理学上不同的情况下升高，例如妊娠，哺乳，C细胞增生，自身免疫性甲状腺炎，晚期肾病，肺癌和前列腺癌以及几种神经内分泌肿瘤。主要的甲状腺髓样肿瘤通常与高剂量的循环降钙素有关，事实上，几乎没有描述非分泌性变体。我们在此报告一例59岁男性，该患者因术前降钙素阴性的多结节性甲状腺肿而接受了全甲状腺切除术，在确定的病理学上显示了甲状腺髓样癌。据我们所知，这是第一例记录非分泌性甲状腺髓样癌的病例，在诊断时和复发时均具有双重阴性标记。文献综述强调了病理学假说，鉴别诊断以及替代性和创新性生物标志物，以鉴定非分泌性甲状腺髓样癌。我们在此报告一例59岁男性，该患者因术前降钙素阴性的多结节性甲状腺肿而接受了全甲状腺切除术，在确定的病理学上显示了甲状腺髓样癌。据我们所知，这是第一例记录非分泌性甲状腺髓样癌的病例，在诊断时和复发时均具有双重阴性标记。文献综述强调了病理学假说，鉴别诊断以及替代性和创新性生物标志物，以鉴定非分泌性甲状腺髓样癌。我们在此报告一例59岁男性，该患者因术前降钙素阴性的多结节性甲状腺肿而接受了全甲状腺切除术，在确定的病理学上显示了甲状腺髓样癌。据我们所知，这是第一例记录非分泌性甲状腺髓样癌的病例，在诊断时和复发时均具有双重阴性标记。文献综述强调了病理学假说，鉴别诊断以及替代性和创新性生物标志物，以鉴定非分泌性甲状腺髓样癌。这是第一例记录非分泌性甲状腺髓样癌的病例，在诊断时和复发时均具有双重阴性标记。文献综述强调了病理学假说，鉴别诊断以及替代性和创新性生物标志物，以鉴定非分泌性甲状腺髓样癌。这是第一例记录非分泌性甲状腺髓样癌的病例，在诊断时和复发时均具有双重阴性标记。文献综述强调了病理学假说，鉴别诊断以及替代性和创新性生物标志物，以鉴定非分泌性甲状腺髓样癌。