Abstract
We describe the case of a primary pulmonary synovial sarcoma in a 52-year-old woman who initially presented with a breast mass. Histologic examination of the breast core needle biopsy specimen revealed a spindle cell neoplasm consistent with synovial sarcoma.
Synovial sarcoma is a rare soft tissue tumor that usually arises in the extremities. Although metastatic spread is common, breast involvement is unusual.
The diagnosis of this tumor is challenging, even with the use of immunohistochemistry, especially when the tumor is located in an atypical site. The STY-SSX fusion gene is unique to synovial sarcoma and can be detected using fluorescence in situ hybridization or reverse transcription-polymerase chain reaction.
The discovery of this tumor in an unexpected site should prompt a search for an alternative primary.