Osteosarcoma pelvis LSBU

Description: Radiology case 4412-3221 72 year old man with pain on walking.
There is a general abnormality of bone architecture in the pelvis with coarsening and increased density. There is loss of normal cortico-medullary distinction. The bone issoftened with protrusio acetabuli, particularly on the left side. There is an additional process that has expanded and destroyed the left ischium. It takes the form of a large soft tissue mass with its centre of radius in the left ischium. There is calcific / ossific density within the mass. The extra density lies above, and separate from, the superior pubic ramus. In this location the bone-forming pathology has extended over obturator internus.