Bone Tumours Malignant Flashcards
What are the features favouring mets over primary malignancy in bone?
Diaphysis, vertebral body and pedicles involved , absence of bone expansion, absence of periosteal rxn, absence of tumour bone formation, absence of large soft tissue mass
What are the radiology findings of chondrosarcoma?
Calcification occurs in 75% of cases on radiography and 92% at CT. Slow growth allows reactive change to occur in the normal bone, so that as endosteal resorption takes place ( Fig. 48.8 ) periosteal new bone is laid down and bone expansion occurs, particularly with more aggressive myxoid tumours ( Fig. 48.9 ). Deep endosteal cortical scalloping (greater than two-thirds) is suggestive of chondrosarcoma as opposed to chondroma.
What are the radiology findings of central osteosarcoma?
Osteosarcoma typically presents as a metaphyseal lesion with a moth-eaten or permeative pattern of bone destruction. The medullary lesion is predominantly lytic but mineralization of the tumour osteoid leads to a characteristic associated medullary sclerosis ( Fig. 48.15A ). Occasionally the intramedullary component shows purely dense sclerosis ( Fig. 48.15B ). Cortical destruction is common, resulting in the development of an eccentric extraosseous mass, which commonly shows typical osseous ‘cloud-like’ matrix mineralization. The density of the extraosseous mass is increased by periosteal reaction, which is usually disorganized or perpendicular to the cortex or producing a ‘sunburst’ appearance. Reactive Codman’s triangles may form at the margin of the lesion.
What are the radiology features of Ewing’s Sarcoma?
The tumour produces a permeative pattern of predominantly lytic bone destruction with a wide zone of transition ( Fig. 48.27A ). The destructive process in bone may be radiographically occult in the most aggressive lesions. The tumour rapidly extends through the cortex producing a large extraosseous, sub-periosteal mass, which is sometimes disproportionate to the degree of medullary involvement. Soft tissue involvement is radiographically evident in 80%. The sub-periosteal tumour mass may cause erosion of the outer cortex, producing so-called ‘saucerization’ ( Fig. 48.27B ). The classic multilaminar (‘onion peel’) periosteal reaction is uncommon, but confirms the periodic activity of the lesion. An incomplete laminar periosteal reaction is more common, with marginal Codman’s triangles. A vertical ‘hair-on-end’ type of periosteal reaction is also classical of Ewing’s sarcoma. Other reported features include cortical thickening and rarely pathological fracture or bone expansion.
