Bone marrow oedema associated with benign and malignant bone tumours.

Bone marrow oedema is associated with a wide variety of pathological processes including both benign and malignant bone tumours. This imaging finding in relation to intraosseous tumours can aid in providing a more focused differential diagnosis. In this review, we will discuss the MR imaging of bone marrow oedema surrounding intraosseous neoplasms. The different pulse sequences used in differentiating underlying tumour from surrounding oedema are discussed along with the role of dynamic contrast enhanced MRI. Benign lesions commonly associated with bone marrow oedema include osteoid osteoma, osteoblastoma, chondroblastoma and Langerhan's cell histiocytosis. Metastases and malignant primary bone tumours such as osteosarcoma, Ewing's sarcoma and chondrosarcoma may also be surrounded by bone marrow oedema. The imaging findings of these conditions are reviewed and illustrated. Finally, the importance of bone marrow oedema in assessment of post chemotherapeutic response is addressed.