Dedifferentiated Chondrosarcoma in the Scapula

Dedifferentiated chondrosarcoma is a rare but highly malignant form of chondrosarcoma with grave prognosis. Early and accurate diagnosis followed by radical surgery seems the only treatment to improve survival. We report a case of dedifferentiated chondrosarcoma in the scapula of a 55-year-old woman presenting with non-specific left shoulder pain. Radiography, computed tomography, and magnetic resonance imaging showed an expansile osteolytic lesion with cortical erosion and internal punctate calcification involving coracoid and glenoid processes. Soft tissue components of the lesion appeared to have invaded the rotator cuff muscles. Computed tomography-guided biopsy confirmed the diagnosis and the tumour was excised with the shoulder joint. Histopathology of the specimen demonstrated intramedullary tumour showing conventional chondrosarcoma admixed with a malignant fibrous histiocytoma-like spindle cell sarcoma. The features were compatible with dedifferentiated chondrosarcoma arising from a conventional chondrosarcoma. Having reviewed the clinical and radiological features of dedifferentiated chondrosarcoma, we stress the importance of radiological imaging features to identify tumour bimorphism suggestive of the diagnosis, and select the site to biopsy.