Synovial sarcoma

Synovial sarcoma is a rare malignant soft tissue tumor that, despite its name, does not arise from synovial tissue. It is a high-grade sarcoma that most commonly occurs in the extremities, particularly around the knee and thigh, though it can develop in virtually any anatomical location including the trunk, head and neck, lungs, and abdominal wall. The tumor is characterized by a specific chromosomal translocation, t(X;18)(p11.2;q11.2), which results in a fusion between the SS18 (SYT) gene on chromosome 18 and one of the SSX genes (SSX1, SSX2, or SSX4) on the X chromosome. This translocation is found in more than 95% of cases and serves as a key diagnostic marker. Histologically, synovial sarcoma can present as monophasic (spindle cell), biphasic (containing both epithelial and spindle cell components), or poorly differentiated subtypes. Symptoms typically include a slowly growing, deep-seated mass that may or may not be painful. The tumor often presents as a palpable swelling near a joint, and patients may experience localized pain, tenderness, or reduced range of motion depending on the tumor's location and size. Because the mass can grow slowly over months to years, diagnosis is frequently delayed. Synovial sarcoma has a propensity for local recurrence and can metastasize, most commonly to the lungs, lymph nodes, and bone. Treatment of synovial sarcoma typically involves a multimodal approach. Wide surgical excision with clear margins is the primary treatment. Adjuvant or neoadjuvant radiation therapy is commonly used to reduce the risk of local recurrence, particularly for larger or higher-grade tumors. Chemotherapy, often with ifosfamide and doxorubicin-based regimens, may be employed in cases of advanced, metastatic, or unresectable disease. Synovial sarcoma is considered one of the more chemosensitive soft tissue sarcomas. Emerging targeted therapies and immunotherapies are under investigation, and the prognosis depends on factors such as tumor size, location, histological subtype, and the presence of metastases at diagnosis. Five-year survival rates vary widely but are generally reported between 50% and 80% for localized disease.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Synovial sarcoma