Popliteal cyst
A Baker's cyst, also called apopliteal cyst, is a fluid-filled swelling that develops at the back of the knee. Knee damage caused by a Sports injuries or a blow to the knee can lead to a Baker's cyst developing.
Treatment for a Baker's cyst isn't needed if you don't have any symptoms. Further treatment will only be needed if you're unable to use your knee. Surgically removing a Bakers cyst isn't easy because they dont have a lining.