These cysts are also called popliteal cysts. They are caused by an accumulation of trapped joint fluid found behind the knee. Baker’s cysts are often associated with arthritis, knee overuse, or knee injury, such as torn cartilage. Inflammation may also be present. Rarely, a bulging or ruptur...
What a sac is filled with determines whether it is a cyst, an abscess, or a tumor. Cysts are usually filled with fluid, such as skin oil, although they may also contain air, water, or semi-solid matter from the body. Abscesses are often the result of an infection and containpus.Tumo...