Osteossarcoma Extraesquelético Retroperitoneal, Um Caso Raro
75 year old man, complaining of weight loss (>10% of initial weight) in the previous months, presence of an abdominal mass in the left flanc associated with pain and non selective anorexia as well as the sensation of post prandial fullness in the past three months. He had a past history of a gastric and an intestinal adenocarcinoma. He was subjected to surgery with the resection of a large mass composed of malignant cells with cystic and solid components (fibrous tissue, cartilage and mature bone). The pathology exam showed it was an extraskeletal retroperitoneal telangiectasic osteosarcoma. No clinical, laboratorial or radiological anomalies were observed after the 12 months follow-up, showing no evidence of local or distant relapse.