Fig. 2

Histological features of thyroid giant cell tumor of soft tissue. A The tumor was composed of mononuclear stromal cells and a large number of multinucleated cells. B Hemorrhagic cystic formation is seen in the nodules, with marked interstitial fibrosis. C Osteoclast-like giant cells can be very large, with more than 50 nuclei. There are recognizable mitotic forms, but the cells exhibit minimal nuclear pleomorphism. D Mononuclear cells are histological and locally spindle shaped, with no atypia nor abnormal mitotic activity (hematoxylin and eosin, with original magnifications of 100×, 100×, 200×, and 200×, respectively)