Minute Thyroid Cancer with Mediastinal Metastasis; A Case Report.

A 58-year-old man complained of hoarseness. He was found to have left vocal cord palsy and a nodule in the left thyroid lobe. US of the thyroid revealed a round tumor with a definite regular boundary echo and an internal echo with a polycystic pattern. CT films showed a noninvasive mass in the left thyroid lobe and a mediastinal mass with a small calcification. No lesion was detected in the right thyroid lobe by US or CT.The preoperative diagnosis was a benign thyroid tumor and a mediastinal tumor. Histological examination showed a follicular adenoma of the left thyroid, a minute papillary carcinoma of the right thyroid and a papillary carcinoma in the mediastinum. The mediastinal tumor had invaded the left recurret nerve and was considered to be a metastasis from the minute carcinoma of the right thyroid lobe.