[Innovations in the classification of soft tissue tumors]

Soft tissue tumors are a very heterogeneous group of tumors. Their classification is regularly updated by the World Health Organization (WHO), most recently in 2020. The current classification of soft tissue tumors emphasizes molecular biological tumor characteristics, which enable tumor-specific treatment. In addition to Ewing's sarcoma, which occurs as bone as well as extra-skeletal soft tissue tumors as a small round cell sarcoma, three other subtypes of undifferentiated, small and round cell sarcomas have been introduced. Some names of the new sarcomas can be derived from the gene mutations. The groups of adipocytic and (myo)fibroblastic tumors have been extended by three further entities. There were further additions to vascular soft tissue tumors, smooth muscle cell tumors, peripheral nerve sheath tumors and tumors of uncertain differentiation. A distinction is made between benign, intermediate locally aggressive, intermediate rarely metastatic and malignant soft tissue tumors.