bone, cases Week 268: Case 1 April 26, 2023 pathadmin 1. Presented by Edward McCarthy, M.D. and prepared by Marc Lewin, M.D.An 18 year old man had a lump in his lower leg which was increasing in firmness over the past several months. A radiograph demonstrated a well defined radiodensity in the back of his knee.Osteogenic sarcomaHeterotopic ossificationChondrosarcomaTumoral calcinosis 1. Presented by Edward McCarthy, M.D. and prepared by Marc Lewin, M.D.An 18 year old man had a lump in his lower leg which was increasing in firmness over the past several months. A radiograph demonstrated a well defined radiodensity in the back of his knee.