Soft tissue tumors (STT) are a heterogeneous group of benign and malignant processes. Some are assumed reactive, others are clearly neoplastic. These lesions account for less than 4 % of all tumors in adult patients and for 7–10 % of all tumors in pediatric patients. More than 99 % of STT are benign, and the incidence of malignant STT is about 4–5 times that of malignant tumors arising from the bone.