Liposarcoma originates in fat cells and is the second most common type of soft tissue cancer. Typically people will notice a painless mass in their soft tissue, for example their abdominal cavity, arm or leg.
Liposarcoma is a malignant soft tissue tumor of fat tissue containing malignant lipoblasts. It usually occurs in the thigh, abdomen area (retroperitoneum) and behind the knee (popliteal fossa). The tumor tissue has four types: myxoid (low grade), round cell (high grade), pleomorphic (giant cell-high grade), and well differentiated (low grade). Patients must undergo all staging studies. The MRI scan is more sensitive than the CT scan for this type of sarcoma. The MRI shows high grade liposarcomas to be more vascular and denser than lower grades. Treatment consists of wide excision of the tumor with radiation therapy and sometimes chemotherapy depending on the tumor size and/or presence of lung metastases. Patients with tumors larger than 8 centimeters usually have preoperative chemotherapy and radiation followed by the surgery and postoperative chemotherapy (MAID protocol). Postoperative radiation is only required if the pathology evaluation reveals positive margins (tumor cells present in the surrounding tissue).