A 25-year-old female with high-grade spindle cell sarcoma of the thyroid persistent after thyroidectomy performed at another hospital was referred to our institute. Chemotherapy followed by surgery with intraoperative radiotherapy and postoperative intensity-modulated radiotherapy were planned within the sarcoma board. Chemotherapy was discontinued after two cycles because of local disease progression and surgery with intraoperative radiotherapy, was anticipated. The treatment was completed with postoperative radiotherapy. After 36 months off-therapy, the patient was free of disease without significant late effects. Thyroid sarcomas are very rare and there is no consensus on their clinical management. Hence, case reports are useful to share treatment options. In this patient case, the histotype and the high-grade disease required a combined therapy program, managed in a multidisciplinary setting.
