12 Soft Tissue Sarcoma	149

12.4.6Therapy

•Due to high frequency of metastatic spread, combined therapy with surgery, chemotherapy, and radiotherapy: see “RMS”

12.4.6.1 Surgical Procedure

• Total resection and regional lymph node biopsy (involvement in 25% of cases)

12.4.6.2 Radiotherapy

• Local irradiation of 50–60 Gy, including positive regional lymph nodes

12.4.6.3 Chemotherapy

•As in rhabdomyosarcoma (see above); without chemotherapy, 75% of patients develop pulmonary metastases within 3 years of diagnosis

12.4.7Prognosis

•Stages I and II: 80% 5-year survival

•Stages III and IV: 17% 5-year survival

•Relapse possible still after 10 years after diagnosis

•Stages III and IV: preoperative high-dose therapy with cisplatin, ifosfamide plus doxorubicin and etoposide leads to a higher rate of long-term survival

12.5Liposarcoma

12.5.1Incidence

•Four percent of all soft tissue sarcomas in childhood

•Peak incidence during infancy and during adolescence

•Ratio of males to females is 2:1

•Often tumor during adulthood

12.5.2Pathology and Cytogenetics

•Origin from precursor cells of lipoblasts with five histological types:

–Well-differentiated type: most frequent form; similar to lipoma; however, with atypical cells together with fibroblasts, spindle cells, and sclerosis

–Myxoid type: monomorphic, fusiform, or starry cells within a mucoid matrix

–Round-cell type: round and oval cells with central nucleus and foamy cytoplasm

–Pleomorphic type: pleomorphic cells with vacuoles, unior multinucleated, eosinophilic cytoplasm

–Mixed type

•Cytogenetics: translocation t(12;16)(q13;p11)