5. Liposarcoma

Liposarcoma is primarily a tumor that occurs) with peak incidence between ages 50 and 70 and equal gender distribution (Fig. 5.1). As described previously (see Chap. 1, Fig. 1.​6), liposarcomas account for approximately 20 % of all soft tissue sarcomas in adults. Anatomic distribution of liposarcoma is wide (Fig. 5.2) and is usually considered to manifest in three biological subtypes. The most common type is well-differentiated liposarcoma (sometimes called atypical lipomatous tumor [ALT]), and its high-grade variant dedifferentiated liposarcoma. The second most common is myxoid (low grade) and round cell (high-grade) liposarcoma. The least common is (high-grade) pleomorphic liposarcoma. Each subtype has a very distinctive morphology, natural history, and genetic changes utilized in diagnosis.