Primary mediastinal synovial sarcoma.

Synovial sarcoma occurs predominantly in the soft tissues of the extremities, but is exceedingly rare in the mediastinum. It has overlapping histological and immunophenotypic features with other tumours in the differential diagnosis. We report a case of a patient who had an incidental finding of such a tumour. Because of the rarity of this tumour in the mediastinum, optimal therapy is unknown and the prognosis remains guarded.