Flank monophasic synovial sarcoma in a filipino patient mimicking a chest wall tumor: a rare diagnostic challenge

Synovial sarcoma (SS) is a rare and aggressive soft tissue malignancy, comprising 5%–10% of all soft tissue sarcomas (STS). It predominantly affects young adults and typically arises in the extremities, with atypical presentations in the trunk, such as the flank, being exceedingly rare.1 Due to its insidious growth and histological resemblance to other spindle cell tumors, SS presents significant diagnostic challenges, leading to delays in treatment. This case underscores the complexity of diagnosing and managing SS in an unusual location, particularly in an older adult.