Melanotic medullary thyroid carcinoma is morphologically defined by the presence of melanin deposits in the cytoplasm of tumor cells. It is an extremely rare variant with only 15 cases described in the literature to date and only one report of diagnosis by fine needle aspiration (FNA) biopsy. A 51-year-old woman presented with neck swelling. An ultrasound examination revealed a single solid nodule in the right thyroid lobe that measured 5.4 × 4.7 × 4.3 cm. Laboratory examination revealed elevated levels of serum calcitonin (8643.0 pg/ml), carcinoembryonic antigen (CEA) (86.2 ng/ml), and chromogranin A (123.2 ng/ml). An FNA biopsy of the thyroid nodule revealed predominantly single plasmacytoid cells with round to oval eccentric nuclei and dark brown intracytoplasmic granules. Immunohistochemical studies with Melan-A performed on a cell block slide confirmed that the granules contained melanin. The tumor cells were also positive for calcitonin, CEA, synaptophysin, AE1/AE3, CAM5.2, and HMB-45(focal); the tumor cells were negative for chromogranin, thyroglobulin, PAX8 and TTF-1. The diagnosis was reported as melanotic variant of medullary thyroid carcinoma. The patient underwent a total thyroidectomy which revealed tumor cell expression of insulinoma-associated protein 1 and confirmed neuroendocrine differentiation. Shortly after she presented with tumor recurrence in the thyroidectomy bed. The tumor cells were positive for only S100, SOX10, and Melan-A. Molecular analysis with the SEMA4 Solid Tumor Panel revealed mutations in the HRAS, PIK3CA, PIK3R1, MYC, and CCND3 genes. The final diagnosis was reported as melanocytic medullary thyroid carcinoma with high grade transformation and loss of epithelial and neuroendocrine expression.

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黑色素性甲状腺髓样癌：一例文献复习报告

黑色素性甲状腺髓样癌的形态学定义为肿瘤细胞细胞质中存在黑色素沉积物。这是一种极为罕见的变异，迄今为止在文献中仅描述了 15 例，并且只有一份通过细针穿刺 (FNA) 活检进行诊断的报告。一名 51 岁的女性因颈部肿胀就诊。超声检查显示右侧甲状腺叶中有一个实性结节，大小为 5.4 × 4.7 × 4.3 cm。实验室检查显示血清降钙素 (8643.0 pg/ml)、癌胚抗原 (CEA) (86.2 ng/ml) 和嗜铬粒蛋白 A (123.2 ng/ml) 水平升高。甲状腺结节的 FNA 活检显示主要为单个浆细胞样细胞，具有圆形至椭圆形偏心核和深棕色胞浆内颗粒。在细胞块载玻片上进行的 Melan-A 免疫组织化学研究证实颗粒含有黑色素。肿瘤细胞也对降钙素、CEA、突触素、AE1/AE3、CAM5.2 和 HMB-45（局灶性）呈阳性；肿瘤细胞对嗜铬粒蛋白、甲状腺球蛋白、PAX8 和 TTF-1 呈阴性。诊断报告为甲状腺髓样癌的黑色素变体。患者接受了全甲状腺切除术，结果显示肿瘤细胞表达胰岛素瘤相关蛋白 1，并证实存在神经内分泌分化。在她出现甲状腺切除术床上的肿瘤复发后不久。肿瘤细胞仅对 S100、SOX10 和 Melan-A 呈阳性。使用 SEMA4 Solid Tumor Panel 进行的分子分析揭示了 HRAS、PIK3CA、PIK3R1、MYC 和 CCND3 基因的突变。