<s>[INST] I have pain behind my knee and slight swelling.  It has been there for over 2 months and I am not real athletic or have not done anything to pull a muscle.  My father and I have a history of cysts in our calf.  Do you think this could be a bakers cyst? [/INST] Dear patientthere is enough possibility of popliteal cyst or baker's cyst. Diagnosis an be confirmed by ultrasound of knee and popiteal fossa. If cyst is small nothing needs to be done. If large it can be removed by open or arthroscopic techniques. Popliteal cyst may be associated with intra articular pathology and Mri of the knee is advisable to rule out it. </s>