[A case of anaplastic carcinoma of the mediastinal goiter]

We reported a case of anaplastic carcinoma of mediastinal goiter. The initial symptom was hoarseness, and thyroid scintigram and venogram revealed mediastinal thyroid malignant tumor, although cervical tumor could not be palpated. Operation was performed with median sternotomy. The size of the tumor was 8 x 6 x 3cm. Histological examination showed papillary adenocarcinoma of left lower pole of the thyroid gland which was transformed into anaplastic carcinoma and extended to the mediastinal cavity. Anaplastic carcinoma of mediastinal goiter is very rare, and our case showed anaplastic transformation from papillary adenocarcinoma.