Abstract
Primary thyroid leiomyosarcoma (LMS) is an extremely rare soft tissue cancer; only 22 cases have been reported in the literature to date. In the current study, the case of an 83-year-old male patient who presented with a neck mass that had grown rapidly over the previous 3 months is reported. The patient underwent thyroid lobectomy twice and two cycles of immunotherapy for the treatment of primary thyroid LMS; however, he succumbed to the disease 5 months after the second surgery. An accurate diagnosis of primary thyroid LMS is difficult, as the disease is often misdiagnosed as anaplastic carcinoma, and requires the combined assessment of clinical, imaging and pathological data. Diagnosis of the current patient with primary thyroid LMS and a comprehensive review of the relevant literature are presented herein.