Local venous invasion of synovial sarcoma in the upper extremity: a case report

Synovial sarcoma is a high-grade malignant soft tissue tumor associated with poor survival that mainly occurs in young adults and adolescents. We report a rare case of forearm synovial sarcoma with local venous invasion in an 87-year-old woman. She presented with a painful enlarging mass in the left forearm. Contrast-enhanced magnetic resonance imaging revealed a 20×10×7 cm lobulated mass involving both the anterior and posterior compartments. Positron emission tomography-computed tomography showed no distant metastasis or regional lymph node involvement. Histological examination confirmed grade 2 monophasic synovial sarcoma. Abnormal enlargement of the cephalic, median cubital, basilic, and brachial veins was observed 5 cm proximal to the tumor. Transhumeral amputation was performed with a 2-cm surgical margin from the proximal end of the enlarged vessels. No tumor cells were identified at the amputation margin. At 12 months after surgery, the patient showed no recurrence or metastasis.