CHONDROSARCOMA OF THE SCAPULA
Clinical appearance: A 30 year old female presented with pain in the right shoulder and swelling during the last 2.5 years.
Physical examination showed right upper extremity’s hyposensitivity, but no muscle weakness nor deep joint reflexes abnormality was indicated.
Radiographs of the right scapula revealed a large soft tissue mass containing ring-like calcification.
CT of the scapula showed a lytic lesion arising from the scapula with disruption of the cortex and an extensive soft tissue mass containing calcification and ossification.
MR showed a large lobulated mass with intermediate signal on T1-w images and a high signal on T2-w images with smaller areas of low signal corresponding to areas of calcification/ossification. Finally, a CT-guided fine needle aspiration (F.N.A.) was performed and confirmed the diagnosis of a grade 1 chondrosarcoma.
Discussion: chondrosarcoma is a malignant bone tumor that usually occurs in patients over the age of 40. Chondrosarcoma rarely affects children , often as a malignant degeneration of an osteochondroma or an enchondroma (more often in diaphyseal aclasia or dyschondrodysplasia respectively).
Chondrosarcomas can also subdivided according to their location into :
a) central: arising within the medullary space and
b) cortical-based: arising on the surface of the affected bone.
There are also some rare types of chondrosarcoma such as mesenchymal, dedifferentiated, and clear cell chondrosarcoma.
On a plain radiograph chondrosarcoma appears as a lytic central or peripheral lesion usually with peripheral scalloping with or without mineralization. The differential diagnosis of a mineralized chondrosarcoma includes only enchondroma and bone infarction.The differential diagnosis of a non mineralized chondrosarcoma is wide and includes almost any bone malignancy such as fibrosarcoma , malignant fibrous histiocytoma , plasmacytoma , metastasis and osteolytic osteosarcoma.
CT is better at assessing soft tissue mass, distribution, configuration and the extent of calcification and ossification as well as the integrity of the overlying cortex.
Furthermore, MR images define the extent of the intraosseous involvement as well as the extent of soft tissue involvement. Recent studies also suggest that contrast–enhanced MR imaging may assist the differentiation between benign and malignant cartilaginous tumors.
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