History A 15-year-old boy noticed a lump over the proximal aspect of his tibia on one leg. On consulting a physician, he explained that the lump had been there for nearly 6 months but had been increasing in size over the recent few weeks. On Examination There is a firm, irregular and tender mass arising from the proximal tibia. The boy describes no pain on palpation of the lump and his range of movement is full. There are no other lumps.
His erythrocyte sedimentation rate (ESR) and serum alkaline phosphatase were raised. X-rays of his knee are shown in the figure. Source: 100 Cases in Orthopedics and Rheumatology The answer is posted in the comment section below. Click here to know more.
