Georgia Subscriber
Answer: Popliteal means of or relating to the hollow part of the leg behind the knee joint. Once you know this, you can choose 719.66 (Other symptoms referable to joint; lower leg). This is the code your ICD-9 index refers you to for a knee joint mass.
Your question is a great reminder always to keep a medical dictionary close at hand. Coding manuals don't cover every medical term--a dictionary allows you to determine the appropriate code based on the part of the anatomy the doctor documents.