150 P. Imbach

12.5.3 Clinical Manifestations

• Tumor mass in any lipomatous tissue, mainly in the thigh and the retroperitoneal area, but also in the area of head and neck, shoulder, chest, foot, and omentum, rarely in the kidney

• Metastatic spread: lung, liver; rarely brain, pleura, pancreas, or bone

12.5.4 Therapy

•Depending on the histological subtype: 70% of patients have the well-differentiated type, which rarely show metastatic spread but sometimes have local relapse

12.5.4.1 Surgical Procedure

• Radical resection if possible

12.5.4.2 Radiotherapy

• In patients with subtotal surgery and histologically unfavorable type: 50–60 Gy irradiation necessary

12.5.4.3 Chemotherapy

•Chemotherapy in undifferentiated forms only, similar procedure to rhabdomyosarcoma (see above)

12.5.5Prognosis

•Depends on the degree of tumor excision and histological type:

–Well-differentiated type: favorable, more than 80% 5-year survival

–Myxoid type: variable, up to 80% 5-year survival

–Round-cell and pleomorphic type: poor prognosis; 15–30% 5-year survival

–Retroperitoneal liposarcoma: poor prognosis

12.6Malignant Peripheral Nerve Sheath Tumor

• Benign variant: Schwannoma

12.6.1Incidence

•In childhood, 3–4% of soft tissue sarcomas

•It often occurs in 5% in children with neurofibromatosis type 1