Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 51 1 2013 01 15 69 72 EN Ali Ghafouri Department of Surgery, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Iran. Taha Anbara Department of Surgery, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Iran. Ali Mir Department of Surgery, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Iran. Marzieh Lashkari Department of Radiation Oncology, Tehran cancer institute, School of Medicine, Tehran University of Medical Sciences, Iran. Mohammad Nazari Department of Surgery, Shariati Hospital, School of Medicine, Tehran University of Medical Sciences, Iran. 2015 09 28 Sarcomas are rare tumors account for about 1% of cancers in adult. Soft tissue sarcomas are the most common one. Synovial sarcoma's incident is about 10% of all sarcomas and most commonly rise from para-articular regions in young adults. Based on our knowledge there have been only two reports of thyroid synovial sarcoma in medical literature. We report a 44-year old woman presented with a rapid growing neck mass. The pathology report revealed sarcoma and the immunohistochemistry (IHC) was compatible with synovial sarcoma. It could be understood that synovial sarcoma can be found in various tissues even if there is no synovial cells. https://acta.tums.ac.ir/index.php/acta/article/view/4020 https://acta.tums.ac.ir/index.php/acta/article/download/4020/3995