Abstract:Objective To investigate the clinical, pathological and imaging features of primary synovial sarcoma(PSS). Methods A retrospective study was conducted on the clinical data of 7 PSS patients treated in the Affiliated Hospital of Nanjing University of Chinese Medicine from June 2015 to April 2020 to analyze the corresponding clinical, pathological and imaging manifestations. Results PSS patients usually suffered from pain. There were 3 cases of occurring near the major joint of lower extremity and 4 cases of locating at rare sites, namely the lateral wall of laryngopharynx, the upper mediastinum, subpleural and plantar regions, respectively. Immunohistochemically, the positive rates of Vimentin, Ki-67, CD99 and Bcl-2 were higher in PSS patients. CT showed the lesions of lobular or nodular shape and large tumor size in 3 cases and the lesions of more than 5 cm in maximum diameter in 6 cases, with clear boundary and cystic and solid masses in all cases. MRI showed hemorrhagic and cystic changes, exhibiting “triple signal sign” and low signal fiber septa in 5 lesions. Diffusion weighted imaging (DWI) showed non-uniform and obvious high signal intensity in 5 lesions and the lower value of apparent diffusion coefficient (ADC) in solid part of the lesions. Conclusion The positive rates of Vimentin, Ki-67, CD99 and Bcl-2 are higher in the patients with PSS demonstrated by immunohistochemistry. The "triple signal sign" and low signal fibrous septa are the characteristic imaging findings of PSS. MRI has a higher diagnostic value for it.