ABSTRACT
S ynovial sarcoma accounts for about 10% of adult soft tissue sarcomas with approximately 200 new cases a year in the UK and 800 in the USA. They occur mainly in adolescence although can present at any age.1,2 The mean age o f patients lies between 30 and 33 years,3 and is reported to range from 11 months4 to 81 years. They occur with a ratio o f 1.2 : 1 male : female. They are characteristically slow growing and typically present as deep-seated painful masses, primarily in juxta-articular locations. Around 90% arise in the extremities with around one third of these presenting around the lcnee joint. Other major sites include the head, neck and pharynx.1 Tumors actually arising within the joint are relatively rare and some synovial sar coma arise in areas with no obvious synovium or other consistent clearly defined tissue. These areas include the abdominal wall, oesophagus, mediastinum, within large veins and the heart. Originally described as arising from synovial tis sue,6 continuity with the synovium has not been demonstrated or supported by ultra struc tural and immunocytochemical studies. Unlike some of the other soft tissue sarcomas, there is no clear resemblance to a specific mesenchymal tissue type and it is not clear what the normal counterpart o f synovial sarcoma cells are. This has led to suggestions to rename the tumor, including “soft tissue carcinosarcoma”.7,8 How ever, the clinical and pathological definition of the entity o f synovial sarcoma is now well established.
