Chondrosarcoma arising in an osteochondroma: an unusual cause of an abdominal mass

Secondary chondrosarcomas are rare tumours, which can develop in up to 2% of patients with single osteochondromas. The rarity of presentation of these tumours to the general surgeon can lead to difficulty and delay in diagnosis. We describe such a tumour presenting as an abdominal mass and discuss the appropriate investigations necessary to establish the diagnosis and plan subsequent management.