Synovial chondrosarcoma arising in synovial chondromatosis of the temporomandibular joint.

Synovial chondromatosis of the temporomandibular joint is rare. Even less commonly documented is the progression of synovial chondromatosis to a synovial chondrosarcoma. The aim of this paper is to present only the third case of synovial chondrosarcoma of the temporomandibular joint. Distinction between these two entities by histology alone is extremely difficult and even though it is advised that the definitive diagnosis should be based on clinical, radiographic and histological evidence, this has proved not to be so simple. The patient, a 63 year old female presented with a swelling associated with her left temporomandibular joint. CT and MRI scans confirmed the presence of a periauricular chondroid mass. Fine needle aspiration biopsy revealed an atypical chondroid lesion that was supicious for a chondrosarcoma. The left temporomandibular joint and surrounding tissues were resected after further imaging and extensive clinical, radiological and cytologic consultations. A diagnosis of synovial chondrosarcoma arising in synovial chondromatosis was made.