What are some imaging manifestations of retroperitoneal metastasis?
Retroperitoneal metastasis may appear as retroperitoneal lymphadenopathy via lymphatic spread, retroperitoneal nodules or masses via hematogenous spread, infiltrative soft tissue due to direct spread from a subjacent organ or tissue, or malignant retroperitoneal fibrosis (RPF) when there is an exuberant desmoplastic reaction to retroperitoneal metastatic foci.