Abdominal and pelvic soft tissue sarcomas metastasize primarily hematogenously. The main organs at risk are liver and lungs. In a much lesser degree, abdominal and pelvic sarcomas metastasize to other soft tissues like muscle and subcutaneous fat or bone. Unlike carcinomas, soft tissue sarcomas rarely spread to lymph nodes.
A particular form of metastasizing seen especially in visceral and gynecological soft tissue sarcomas, and in a lesser degree in retroperitoneal or abdominal wall sarcomas infiltrating the peritoneum, is tranperitoneally. Trans- or intraperitoneal spreading poses a risk for relapse or metastases in the entire abdominal region. Transperitoneal metastases are like other metastases most often the result of advanced disease but these can also be iatrogenic after incomplete resections.