The history, imaging and pathology points to chondrosarcoma as the diagnosis, and therefore wide resection and reconstruction is the most appropriate treatment.
Chondrosarcoma tends to occur in an older individuals and the most common sites of origin are the femur, tibia, humerus, ribs, scapula then pelvis. Chondrosarcomas grow slowly and patients present with dull aching pain.
X-rays typically have a subtle, radiolucent, permeative lesion or may have hazy or speckled calcifications with either a diffuse "salt & pepper" pattern or a more discrete "popcorn" pattern. The MRI defines the amount of marrow and soft-tissue involvment, and typically has high T2 signal intensity. Bone scintigraphy will be positive.
In pathological sections, low-power imaging demonstrates lobulated clusters of chondrocytes, and high-power imaging demonstrates a bland cellular appearance, extensive basophilic cytoplasm, and no mitotic figures (low grade chondrosarcoma).
In terms of treatment, low-grade tumors usually respond well to wide resection and reconstruction of limb. Chemotherapy is usually not used except in rare cases of certain chondrosarcoma subtypes (mesenchymal chondrosarcoma). Radiation therapy is not very effective against chondrosarcoma.
Menedez LR (ed): Orthopaedic Knowledge Update: Musuloskeletal Tumors. Rosemont, IL, American Academy of Orthopedic Surgeons, 2002, pp 305-312
Simon MA, Springfield D (eds): Surgery for bone and soft-tissue tumors. Philadelphia, PA Lippincott-Raven, 1998, 756pp.