Occult pulmonary synovial sarcoma confirmed by molecular techniques.

We report a unique case of a minute, occult synovial sarcoma of the lung detected intraoperatively during a pneumothorax repair in a 17-year-old boy. No alternative primary site could be detected upon complete body imaging studies and physical examinations. The diagnosis was confirmed by demonstration of the characteristic SYT/SSX gene fusion by reverse transcriptase polymerase chain reaction (RT-PCR) performed upon RNA extracted from the paraffin block of the biopsy. This case demonstrates the utility of this technique in diagnostic pathology.