Primary Ewing Sarcoma of the Thyroid-Eight Cases in a Decade: A Case Report and Literature Review.

Sarcomas represent less than 1% of all malignant tumors found in the thyroid. Of these, primary extraosseoussarcoma has been reported only a few times in the past decade. We present the case of a 34-year-old male who had a fast-growing hard mass in the lower left neck. FNA was inconclusive. Core needle biopsy revealed the diagnosis of an Ewing sarcoma/primitive neuroectodermal tumor. Mutation of EWSR1 was confirmed using the FISH method. Following treatment by neoadjuvant chemotherapy, we observed clinical, radiological, and finally histopathological remission. This was followed by a left-sided isthmolobectomy with unilateral cervical lymph node dissection by lateral lymphadenectomy, which revealed no residual disease. Posttreatment radiotherapy was administered but discontinued upon the patient's request. After 18 months of observation, the patient had no recurrence or metastasis and required l-thyroxine supplementation. We discuss our case using a comparative literature review to the few other known case reports.