髓样甲状腺癌(MTC)是一种起源于滤泡旁C细胞的神经内分泌肿瘤。钙卫素(Ctn)和癌胚抗原(CEA)是监测MTC病例的有用生物标志物。本文描述了一名48岁的女性，2014年出现双侧甲状腺结节。细针穿刺报告对MTC持怀疑态度；初步实验室评估显示血清Ctn水平为1567 pg/mL。经过临床排除2型多发性内分泌肿瘤综合征，患者接受了全甲状腺切除术和颈部淋巴结清扫术。最终病理诊断为无血管侵犯和淋巴结受累的右叶MTC。在定期随访中，自2014年至2021年，Ctn和CEA水平一直无法检测出来，重复的颈部超声检查结果正常。由于患者于2016年肝酶升高，接受了胃肠科医生的进一步评估。腹盆超声检查显示肝实质粗糙回声，胆管正常。肝纤维分析显示低纤维化评分(7kPa)。建议患者使用尿胆酸。根据2020年10月有胆汁淤积模式的肝酶逐渐升高，进行了肝活检，显示伴有原发性胆汁性胆管炎(PBC)背景的微小神经内分泌样细胞巢。免疫组化染色对嗜铬素A(CgA)和突触素呈阳性，对Ctn、CEA和甲状腺球蛋白呈阴性。进一步的影像学检查未能揭示身体内的神经内分泌肿瘤部位。考虑到正常体格检查、影像学结果以及Ctn、CEA、CgA和降钙素原水平正常，将患者管理为PBC。在MTC患者的随访过程中，我们报道了肝酶逐渐升高并呈胆汁淤积模式的情况。肝活检显示存在背景为PBC的神经内分泌样细胞巢，这些发现可能表明胆管细胞增殖获得神经内分泌表型。© 2023 BioMed Central Ltd.，Springer Nature的一部分。

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that originates from parafollicular C-cells. Calcitonin (Ctn) and carcinoembryonic antigen (CEA) are useful biomarkers for monitoring MTC cases.Here, we describe a 48-year-old woman, who presented in 2014 with bilateral thyroid nodules. Report of fine needle aspiration was suspicious for MTC; initial laboratory evaluation showed serum Ctn level of 1567 pg/mL. After excluding type 2 multiple endocrine neoplasia syndrome clinically, total thyroidectomy and neck lymph node dissection were performed. The final histopathological diagnosis was right lobe MTC with neither vascular invasion nor lymph node involvement. On regular follow-up visits, Ctn and CEA levels have been undetectable, and repeated cervical ultrasonographic exams were unremarkable from 2014 to 2021. As liver enzymes became elevated in 2016, the patient was further evaluated by a gastroenterologist. Abdominopelvic ultrasonography revealed a coarse echo pattern of the liver parenchyma with normal bile ducts. A liver fibroscan showed a low fibrosis score (7kPa). The patient was recommended to use ursodeoxycholic acid. According to the progressive rise of liver enzymes with a cholestatic pattern in October 2020, a liver biopsy was performed that showed tiny nests of neuroendocrine-like cells with a background of primary biliary cholangitis (PBC). Immunohistochemical stainings were positive for chromogranin A (CgA), and synaptophysin and negative for Ctn, CEA, and thyroglobulin. Further imaging investigations did not reveal any site of a neuroendocrine tumor in the body. Considering normal physical exam, imaging findings, as well as normal serum levels of Ctn, CEA, CgA, and procalcitonin, the patient was managed as a PBC.In follow-up of a patient with MTC, we reported progressively increased liver enzymes with a cholestatic pattern. Liver biopsy revealed nests of neuroendocrine-like cells with a background of PBC, the findings that might suggest acquiring neuroendocrine phenotype by proliferating cholangiocytes.© 2023. BioMed Central Ltd., part of Springer Nature.