A 10 year old boy is presenting for unilateral right leg pain with limp for the past 3 weeks. He has no past medical history. He had trauma when playing soccer  a week prior to the symptoms. The pain is dull and mainly over night. The patient has no fever. Review of systems (ROS) reveals no night sweats, weight loss, or fatigue. The joint exam shows a palpable mass over the right tibia. Labs show an elevation of LDH and alkaline phosphatase. Patient had normal ESR, CRP and CBC.