“…These are usually benign tu-mors; however, malignant GCTs have been reported [9,10]. Criteria for malignancy in GCT include: size over 4 cm, increased cellularity, mitoses, nuclear pleomorphism, prominent spindled pattern, and necrosis [10,11]. Only a few cases of GCT arising within the thyroid have been documented in the literature (Table 1) [3][4][5][6].…”