title: Retroperitoneal mass.
mesh_terms: D000328:Adult; D006801:Humans; D008297:Male; D009362:Neoplasm Metastasis; D012186:Retroperitoneal Neoplasms / Q000601:surgery*; D013724:Teratoma / Q000601:surgery*; D013736:Testicular Neoplasms / Q000601:surgery*