Concerning two cases of liposarcomas developing in the retroperitoneal
space, the characteristics of these rare tumors are reviewed. They ar
e the most frequent mesenchymal tumors. Often, they are uncovered by p
alpable abdominal mass or when they compress adjoining organs. Compute
d tomography has proved valuable in the diagnosis of these lesions. Su
rgical removal is the treatment of choice. Recurences are frequent and
prognosis is poor.