A finding about one or more characteristics of soft tissue sarcoma, following the rules of the TNM AJCC v8 classification system. This classification system applies to soft tissue sarcomas that arise in the following areas: head and neck, trunk and extremities, gastrointestinal tract, genitourinary tract, viscera and retroperitoneum, gynecologic sites, breast, lung, pleura, mediastinum, and other unusual histologies and sites. It does not apply to desmoid tumor/deep fibromatosis (no AJCC staging system available) and Kaposi sarcoma (no AJCC staging system available; AIDS Clinical Trials Group system TIS (tumor, immune system, systemic illness) staging may be used). (from AJCC 8th Ed.) [from NCI]