Liposarcoma Cancer

Introduction

Liposarcoma is one of the least frequent nonrhabdomyosarcoma soft tissue sarcomas that occur in childhood; it comprises less than 5% of all soft tissue sarcomas in childhood. Surgical excision is the primary treatment, and prognosis depends on the histologic subtype and degree of resection. For patients with residual disease, radiotherapy has been used.

Pathophysiology

Liposarcoma is a lipogenic tumor of large deep-seated connective tissue spaces. The 3 major locations in which liposarcomas are found are the lower extremities, the retroperitoneal region, and the shoulder area. The favored sites of occurrence in the lower extremities include the popliteal fossa and medial thigh. The most common retroperitoneal location is the perineal region. Occasionally, tumors may originate in the subcutis of shoulder, neck, and facial areas. Children tend to have a higher incidence of lower extremity tumors.3  

Well-differentiated liposarcomas have ring or marker chromosomes commonly derived from 1q and 12q13-15.The consistent cytogenetic abnormality in myxoid liposarcoma is translocation. This involves fusion of the transcription factor gene CHOP, which is essential for adipocytic differentiation, to the translocated in liposarcoma (TLS) gene on chromosome 16.5 In about 2% of cases, CHOP may fuse with the EWS gene on chromosome 22 in translocation.

These cytogenetic abnormalities have also been reported in the more aggressive round-cell liposarcoma; myxoid and round cell liposarcoma form a clear spectrum with regard to disease aggressiveness. Pleomorphic liposarcoma usually lacks this distinct translocation and appears to be biologically closer to other aggressive pleomorphic sarcomas(Gebhardt 2004).

Frequency

United States

In children, liposarcomas are rare and comprise fewer than 5% of soft tissue sarcomas.

Overall, around 100 cases of childhood liposarcoma have been reported in the literature, usually in the second decade of life. At a large New York Cancer Hospital, 18 cases of liposarcoma were reported in patients aged 22 years or younger over a period of 4 decades.7

Mortality/Morbidity

Due to its rarity, survival data for liposarcoma patients are often extrapolated from small series or from adult data. As with other childhood nonrhabdomyosarcoma soft tissue sarcomas, outcome is linked to various prognostic factors, including stage and grade. Complete surgical resection is crucial. The estimated 5-year survival rates for nonmetastatic, completely resected extremity tumors are impacted by histologic subtype and are as follows:

Pleomorphic tumors - 50%

Round-cell tumors - 50%

Myxoid tumors - 80%

Well-differentiated tumors - 100% 

Local recurrence following resection is common and may be avoided by wide excision or adjuvant radiation.

Metastatic spread varies but commonly occurs to the lungs in high-grade pleomorphic tumors. Lymphatic spread is not seen. Myxoid liposarcoma is often considered intermediate grade but may still metastasize in 10-35% patients, sometimes to extrapulmonary soft tissue sites, such as the retroperitoneum or chest wall9 or even brain and spine.

Sex

In the several small series reported, gender predominance varies; assessing an accurate male-to-female ratio is not currently possible.

Age

Overall, the average age at presentation is 50 years. Liposarcomas are rarely seen in the teenage years and are almost never found in patients younger than 10 years. Earlier reports of liposarcoma in infancy were mostly thought to be lipoblastomatosis upon review.3

Clinical

History

Presentation varies, but the tumor usually presents as a painless slow-growing lesion. Only 10-15% patients have a painful ...