I am 73 yrs. old 250 lbs.. I have a small lump about the size of a ball (about half the size of a table tennis ball) on the outside of the left knee area, [Total Knee 2004]. It has grown in about 2 months It is hard and somewhat painful when touched, difficult to walk 200 yards or so. Orthopedic Surgeon opened the area, 4" incision and said, " I have not seen anything like this in all my years!" It was like a jell substance 3 colors orange,tan,red, all the way to the bone and no idea where it originated from! Altar Sound showed a solid Cyst. He removed what he could and stitched me up. This had all been sent to the lab, all negative for Cancer, Disease, and Infection! I still have a bulge on side of knee. It is still painful to walk any distance. He has me in therapy 2 weeks now, not much help also wearing a Knee brace. Therapist tested for strength which was very good.I was in DaNang, Vietnam, Agent Orange in 1963. I had Prostate Cancer, Gleason Score 8 Radical removed April 2010 3 Month later PSA 1.8 high risk fast growing, had 36 Radical Treatments Radiation. Could some of my problems be related to Agent Orange or another type of Virus? Help!!