[Retroperitoneal malignant fibrous histiocytoma with contiguous organs infiltration]

Retroperitoneal tumours are extremely rare neoplasms, most of them malignant. We described the case of a 48-year-old man with a large retroperitoneal mass detected during the study of a constitutional syndrome. The mass was treated surgerically and pathological diagnosis was malignant fibrous histiocytoma. Literature is reviewed and clinical features, histological findings, radiological techniques and therapeutic management are analyzed.