Understanding Synovial Sarcoma Symptoms and Treatment Options for Foot and Ankle

There are many reasons patients seek attention and make an appointment to see a podiatrist, one of those reasons is a new bump or swelling of the foot. Most of the time it's related to a fibroma, neuroma, venous swelling, etc, but in very rare cases it's due to cancer of the foot or ankle. I wanted to take this time to educate patients about the most common malignant mesenchymal tumor called Synovial Sarcoma. This is a rare condition that can arise in the deep tissues of the arms, legs, and feet. It has an annual incidence of 2.57 cases per 100,000 and primarily affects young individuals between the ages of 15 and 40, with a higher prevalence in males. Fewer than 500 cases are diagnosed each year in the United States. While synovial sarcomas represent only about 5 % of all soft tissue sarcomas, they account for approximately 13 % of soft tissue sarcomas occurring in the extremities. Notably, synovial sarcoma is the most frequently diagnosed soft tissue cancer in the foot and ankle region. Less commonly, it may also develop in the head, neck, chest, abdomen, pelvis, or back, and in rare cases, within visceral organs such as the lungs.

While benign soft tissue masses are far more common in the foot and ankle, malignant tumors such as synovial sarcoma must be considered in the differential diagnosis, especially in the presence of persistent or enlarging lesions. Typical symptoms are chronic pain and swelling near the foot.

Typically, patients will need an X-ray and then a MRI to assess the tumor, BUT a definitive diagnosis is established only after histopathological and molecular analysis following surgical excision, underscoring the importance of early tissue diagnosis via biopsy.

Following the initial diagnosis, most patients require wide re-excision of the tumor bed with final pathology confirming negative margins, eliminating the need for adjuvant radiation therapy. While radiotherapy remains an important component of treatment in cases of high-grade or incompletely excised tumors, it may be safely omitted when complete resection is achieved, and there is no evidence of metastatic disease, as supported by an oncologist. Most patients will be placed on a surveillance protocol, including serial MRI and chest CT imaging, to monitor for local recurrence or distant metastasis.

Not all masses are malignant tumors, BUT synovial sarcoma remains a rare entity in foot and ankle pathology, which poses significant diagnostic and therapeutic challenges. Early recognition, appropriate biopsy, and multidisciplinary treatment planning are critical to optimizing outcomes. The importance of obtaining the diagnosis and establishing a collaboration between foot and ankle surgeons, radiologists, pathologists, and oncologists is paramount for successful management.

Darryl Martins DPM FACFAS