A pelvic soft tissue mass may be a metastatic tumor, but it may also be the presence of an inflammatory mass, a tumor mass, a congenital anomaly, or an obstructive mass. 1. Inflammatory mass: this is mainly caused by organ inflammation, so pelvic soft tissue mass may be pelvic lymph node tuberculosis, tuberculous pelvic inflammation, appendiceal abscess, pelvic abscess, ovarian abscess and other conditions. 2. Tumor mass: there are many organs in the pelvis, and various kinds of tumors can occur, so pelvic soft tissue mass includes bladder cancer, endometrial cancer, colon cancer, ovarian cancer, uterine leiomyoma, retroperitoneal tumor, pelvic lymphoma, ureteral tumor, pelvic metastatic tumor and so on. 3. Congenital abnormality: pelvic soft tissue mass may be caused by congenital renal cyst, renal prolapse, ectopic renal mesenteric swelling and so on. 4. Obstructive lumps: Obstructive lumps are mainly caused by the obstruction of hollow organs such as intestines, such as intestinal torsion, intussusception, intestinal obstruction, urinary retention and so on, which can also lead to the appearance of soft tissue lumps in the pelvis. It is recommended that once the diagnosis of soft tissue masses in the pelvis is confirmed, treatment should be actively carried out to avoid delaying the condition.