A malignant lipomatous neoplasm that arises in fat cells in deep soft tissue retroperitoneum.|A malignant tumor derived from primitive or embryonal lipoblastic cells. It may be composed of well-differentiated fat cells or may be dedifferentiated: myxoid (LIPOSARCOMA, MYXOID), round-celled, or pleomorphic, usually in association with a rich network of capillaries. Recurrences are common and dedifferentiated liposarcomas metastasize to the lungs or serosal surfaces. (From Dorland, 27th ed; Stedman, 25th ed)|A usually painless malignant tumor that arises from adipose tissue. Microscopically, it may contain a spectrum of neoplastic adipocytes ranging from lipoblasts to pleomorphic malignant adipocytes. Representative morphologic variants include: well differentiated, dedifferentiated, pleomorphic, and myxoid/round cell liposarcoma. The metastatic potential is higher in less differentiated tumors. (Experimental Factor Ontology, EFO_0000569)
