Liposarcoma, gross specimen. 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 specimen photograph shows well-differentiated liposarcoma. It is a large (14 cm diameter), well-circumscribed, multilobulated mass with yellow-orange colour, resembling normal fat. It arose in the deep soft tissues of the thigh in an elderly patient. Overlying skin can be seen on the left edge of each slice.