Liposarcoma is the most common soft tissue sarcoma in adults (20% of all adult STS). This is a rare tumor in children and usually low grade in this setting.
Liposarcoma is a lipogenic tumor which is subclassified into four main histological groups:
- Well differentiated liposarcoma (lipoma like and sclerosing types)
- Myxoid round cell liposarcoma
- Pleomorphic liposarcoma
- De-differentiated liposarcoma
The histological group predicts the clinical course of the disease and the prognosis.
1. Well differentiated liposarcoma (lipoma like and sclerosing types)
- Low grade malignancy
- May recur locally but do not metastasize
- Characterized in 90% of tumors by the reciprocal chromosomal translocation t(12;16)(q13;p11)
- This translocation creates the FUS-DDIT3 chimeric gene
- Round cell liposarcoma is a variant of this tumor which behaves aggressively and may be associated with intra-abdominal and pelvic metastases. Staging investigations should include a CT scan of the abdomen and pelvis as well as the chest.
- Many tumors contain both components of myxoid and round cell liposarcoma
- In the absence of a round cell component, myxoid sarcoma has a good prognosis
3. Pleomorphic liposarcoma
- Highly malignant with a disorderly growth pattern and extensive cellular pleomorphism
- Surgery is the most important therapy for liposarcoma
- The role of adjuvant chemotherapy for liposarcoma is poorly defined