Two cases of rare thyroid malignancy-case report.

We report 2 cases of rare thyroid malignancy: angiosarcoma and myoepithelial carcinoma (MC). Thyroid angiosarcomas (TAS) is extremely rare and comprises less than 1% of primary thyroid cancer worldwide. MC usually presents as a slow-growing painless mass arising in the salivary glands. It has not been reported in the thyroid gland. The first case describes a 59-year-old patient who was admitted to hospital with the discovery of thyroid nodule for 1 month. The tumor thrombus was found in the left internal jugular vein and superior thyroid artery during the operation. Diagnosis of angiosarcoma of the thyroid was based on positive endothelial markers such as thrombomodulin and CD31 after total thyroidectomy. The left internal jugular vein, left recurrent laryngeal nerve and anterior cervical banding muscle were invaded by thyroid tumor. No lymph node metastasis was observed. The patient died after 4 years. The second case describes a 55-year-old woman who presented with the discovery of thyroid nodule for 1 month. Right thyroid lobectomy and right neck lymph node functional dissection were carried out. The results from postoperative pathology revealed that papillary carcinoma in right lobe of thyroid and MC next to thyroid were found. Besides, the metastasis of MC was observed at right II-IV level and right VI level. Five years later, the patient was re-admitted to hospital, primarily due to the discovery of anterior cervical tumor for one year. Then, she underwent left thyroid lobectomy and right tumor resection. Postoperative routine pathology showed recurrent MC in the right thyroid. After surgery and radiotherapy, the patient was followed up for 2 years. Angiosarcoma and myoepithelioma should be kept in mind in diagnosis of thyroid malignant tumor.