Synovial osteochondromatosis of the knee and synovial chondrosarcoma. Report of 2 cases

The possible transformation of synovial osteochondromatosis into chondrosarcoma is rarely reported in the literature, as well as the coexistence of the two entities. The authors have observed two such cases. The first one was discovered by arthroscopy in the course of a synovial osteochondromatosis associated with a posterior tumour proved secondarily as being a chondrosarcoma. On the contrary, the second case presented as a destroying tumour invading the entire joint and proved secondarily as being a benign osteochondromatosis. Cartilaginous masses very important may lead to bone destruction in the course of benign osteochondromatosis. However, in such cases, the possibility of an associated or a secondary chondrosarcoma must be looked for using radiology, arthroscopy and microscope examination.