thanks for your query
Lump in knee can be due to several different conditions. It is also known as bakers cyst.
A Baker’s cyst is a collection of synovial fluid
(the fluid that is present within joint spaces) that bulges out through the back of the knee joint and can be felt as a lump behind the knee. Knee injuries, arthritis
, damage to the cartilage
of the knee, and other problems can all result in the development of a Baker’s cyst. It may be painful or may not produce any other symptoms.
Other possible causes of a lump on the knee include abscesses (infections); tumors of the skin, soft tissue
, or bones; bleeding; or deformity
of the joint accompanying a fracture or other injury to your knee.But they are associated with other symptoms also.
I would suggest you X-ray of knee before proceeding to further treatment.
I hope this will help