<prompt> Elys cysts are a feature of:Osteoarthritis of TMJChronic suppurative osteomyelitisFibrous dysplasiaGorlin-Goltz syndrome  <response>: In severe degenerative joint disease DJD, the glenoid fossa may appear grossly enlarged because of erosion of the posterior slope of the articular eminence. This erosion may allow the condylar head to move forward and superiorly into an abnormal anterior position that may result in an anterior open bite. The condyle may also be markedly diminished in size and altered in shape because of severe erosions. In some cases, small, round, radiolucent areas with irregular margins surrounded by a varying area of increased density are visible deep to the articulating surfaces. These lesions are called Ely cysts or subchondral bone cysts, but they are not true cysts; they are areas of degeneration that contain fibrous tissue, granulation tissue, and osteoid.Oral radiology ; White and Pharaoh 7th edition page no: 509 