Clinicopathological analysis of 12 cases of children synovial sarcoma

Objective To investigate histopathological characteristics, and differential diagnoses of childhood synovial sarcoma. Methods HE staining, immunohistochemical staining and fusion gene detection by FISH were performed in 12 cases of synovial sarcoma in childhood at Beijing Children′s Hospital from 2016 to 2018. Results There were 6 cases of biphasic type, 1 case of monophasic epithelial type, 3 cases of monophasic spindle cell type and 2 cases of poorly differentiated synovial sarcomas. EMA, CKpan, bcl-2, CD99, TLE1 and CD34 immunostain positivities were observed in 10/12, 9/12, 12/12, 10/12, 10/12 and 0/12 cases respectively. Unique INI1 immunohistochemical staining was observed in 9/12 cases. SS18-SSX gene fusion was detected in 8 of 11 cases by FISH. Conclusions Synovial sarcoma is rare in children. Histological morphology combined with immunohistochemistry and FISH SS18-SSX fusion gene detection are important for the diagnosis and differential diagnosis of synovial sarcoma in children. Key words: Sarcoma, synovial; Immunohistochemistry; Pathology, molecular