Rafaey Wania, Munir Alvi Asim, Siddiqi Ahmed Imran, Shafiq Waqas, Irfan Hira
Endocrinology, Diabetes and Metabolism, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, PAK.
Cureus. 2022 Nov 30;14(11):e32088. doi: 10.7759/cureus.32088. eCollection 2022 Nov.
Medullary carcinoma of the thyroid is a rare neuroendocrine carcinoma that originates from the malignant proliferation of parafollicular C cells. In almost 100% of the cases, medullary carcinoma of the thyroid is associated with high levels of calcitonin and carcinoembryonic acid (CEA). Both carcinoembryonic antigen and calcitonin are used for the diagnosis and surveillance of medullary carcinoma of the thyroid. Calcitonin-negative medullary carcinoma of the thyroid is an extremely rare entity that is characterized by classic medullary carcinoma of the thyroid morphology without raised serum calcitonin levels. We describe the case of a middle-aged lady who presented with a few-month history of neck swelling associated with compressive symptoms. CT of the neck showed a large right thyroid nodule with central necrosis and retrosternal extension to the superior mediastinum. There was also a 360-degree encasement of the right common carotid artery. She underwent fine needle aspiration (FNAC) of the right thyroid nodule, and histopathology showed typical features of medullary carcinoma of the thyroid. Immunohistochemical staining for calcitonin and carcinoembryonic antigen was negative but positive for other neuroendocrine markers, i.e., synaptophysin and chromogranin A. Serum calcitonin and carcinoembryonic antigen levels were also in the normal range. So, a rare diagnosis of calcitonin-negative medullary carcinoma of the thyroid was made. As the disease was inoperable because of vascular encasement, a plan for external beam radiation therapy (ERBT) to the neck was made. Medullary carcinoma of the thyroid with normal serum levels of calcitonin is a very rare entity, with only a few cases reported in the literature. In this case report, we have presented a rare case of medullary thyroid carcinoma (MTC) with normal-range serum calcitonin levels, how it was diagnosed, and how to follow up postoperatively.
甲状腺髓样癌是一种罕见的神经内分泌癌，起源于滤泡旁C细胞的恶性增殖。在几乎100%的病例中，甲状腺髓样癌与降钙素和癌胚抗原（CEA）水平升高有关。癌胚抗原和降钙素均用于甲状腺髓样癌的诊断和监测。降钙素阴性的甲状腺髓样癌是一种极其罕见的实体，其特征是具有典型的甲状腺髓样癌形态，但血清降钙素水平未升高。我们描述了一位中年女性的病例，她有几个月的颈部肿胀病史，并伴有压迫症状。颈部CT显示右侧甲状腺有一个大结节，伴有中央坏死，并向后纵隔延伸至纵隔上部。右侧颈总动脉也被360度包绕。她接受了右侧甲状腺结节的细针穿刺抽吸（FNAC），组织病理学显示为典型的甲状腺髓样癌特征。降钙素和癌胚抗原的免疫组化染色为阴性，但其他神经内分泌标志物，即突触素和嗜铬粒蛋白A为阳性。血清降钙素和癌胚抗原水平也在正常范围内。因此，诊断为罕见的降钙素阴性甲状腺髓样癌。由于血管被包绕，该疾病无法手术，因此制定了颈部外照射放疗（ERBT）计划。血清降钙素水平正常的甲状腺髓样癌是一种非常罕见的实体，文献中仅报道了少数病例。在本病例报告中，我们展示了一例血清降钙素水平在正常范围内的罕见甲状腺髓样癌（MTC）病例，介绍了其诊断方法以及术后如何随访。
