Bone infarct is a aseptic or avascular necrosis of bone. It is relatively common orthopaedic finding and is often idiopathic but can be seen secondary to an underlying condition such as alcoholism, corticosteroid use, or Caisson’s disease. It can occur anywhere in the skeleton but are predominately seen around the hip and knee. Secondary sarcoma arising in association with a preexisting bone infarct is extremely rare, accounting for less than one percent of all bone sarcomas. It’s histology usually reflects a high-grade sarcoma, such as malignant fibrous histiocytoma of bone, fibrosarcoma or conventional osteosarcoma. Low-grade sarcoma arising from bone infarct has not been described well in the literature.We present a 65year old female patient with bone infarct in her right distal femur and proximal tibia, from which a low-grade central osteosarcoma developed. A histologic diagnosis of low-grade central osteosarcoma was confirmed by immunohistochemical expression of MDM2 and CDK4. She had also pathological fracture in right distal femur.

Keywords : Bone Infarct, Malignant Fibrous Histiocytoma, Fibrosarcoma, Osteosarcoma, MDM2, CDK4.