Primary leiomyosarcoma of the thyroid is a very rare tumour with an unfavourable prognosis. We present a sixty-year-old woman with a localised primary thyroid leiomyosarcoma. Despite a complete resection, a recurrence of the tumour was noticed six months later. After induction chemotherapy with ifosfamide and doxorubicin, the patient had renewed extensive surgery with removal of a tumour remnant and several lymph nodes. This was followed by radiotherapy. Eighteen months after diagnosis the patient is still alive and free of tumour on PET-CT. The case illustrates the high recurrence potential of a primary thyroid leiomyosarcoma despite a complete initial resection, but also the success of aggressive combined treatment.

(BELG J MED ONCOL 2018;12(2):75–78)