Dr. James J. Pollard: A 77-year-old white male complained of swelling of the left knee for one and one-half years. This began when he injured his left knee in a fall. There had been a gradual increase of painless swelling which was not incapacitating. X-ray examination done elsewhere following the injury was interpreted as negative. The examination was repeated six months later and at that time an abnormality was questioned and operation recommended, but this was refused.
On admission to Massachusetts General Hospital, physical examination showed a massive, fusiform swelling about the left knee and the tissues around the proximal tibia. There was a discrete, painless mass measuring 4 cm by 4 cm attached to the proximal tibia in the popliteal space. The hemoglobin, white blood cell count, sedimentation rate, serum calcium, phosphorus, alkaline phosphatase, and acid phosphatase levels were normal.
Interpretation of the knee films (Fig 1 and 2)