Clinical suspicion of bilateral carotid body paraganglioma and an unexpected histologic diagnosis.

Carotid body tumor (CBT) is the most common of the head and neck paragangliomas (PGLs). Conversely, synovial sarcomas are usually located around knee and ankle joint and rare variants occur in the oral cavity. A 68-year-old man presented with a left voluminous painless cervical mass. The diagnosis of CBT of type III Shamblin was suspected. The cervical mass was removed en bloc. Unexpectedly, pathologic examination showed monophasic synovial sarcoma. Excision of PGLs remains the therapy of choice, especially to make a correct histologic diagnosis.