A Rare Case of Humerus Synovial Sarcoma Originated from Bone Tissue: Case Report.

Synovial sarcoma (SS) is a malignant mesenchymal neoplasm that is relatively common in the distal extremities. Primary SS of bone is an extremely rare finding. Here in this report, we present a 44-year-old male patient referred with bone and later bone fracture that was finally diagnosed with primary SS of thumerus. So far, 13 documented cases of primary SS of the bone have been reported. The current case is the second known case of primary SS of humerus. Our case was treated with both neoadjuvant and adjuvant chemotherapies associated with surgical tumor removal and prosthesis implantation. Follow-up of the case demonstrated significant remission but with late metastasis and subsequent advanced chemotherapy regimens.