Pleomorphic liposarcoma, light micrograph. Liposarcoma is one of the most common sarcomas of adulthood. It arises from fat in deep soft tissues of the extremities and retroperitoneum. The patients are usually in their sixth or seventh decades of life. Histologically, liposarcomas are subdivided into well-differentiated, myxoid and pleomorphic subtypes. This image shows pleomorphic liposarcoma. It is the least common subtype. There is extreme degree of cellular pleomorphism, with lipoblasts containing bizarre, scalloped, hyperchromatic nuclei and multinucleated tumour giant cells. There is close resemblance to undifferentiated pleomorphic sarcoma or even rhabdomyosarcoma. Magnification: x400.