Results: Histology showed multinodular goiter. In the largest hyperplastic adenomatous nodule (left lobe, diameter mm 53), multiple solide yellow-orange areas were detected grossly. These areas were microscopically composed of sheets of large cells with clear cytoplasm and small hyperchromic nuclei, with a focally infiltrative growth pattern. At immunohistochemistry clear cells were negative for TTF1, HBME1, galectin-3 and positive for CD10.