[Clinical Picture] Extraskeletal osteosarcoma of primary retroperitoneal origin

A 53-year-old man with a history of ischaemic heart disease presented to his general practitioner with a 6-week history of right-sided abdominal discomfort, associated with worsening constipation and early satiety. He denied weight loss and pain or swelling in the extremities. No family history of malignancy was reported. On examination, we noted a large, hard mass in the right iliac fossa, with no clinical features of ascites.