The occurrence of primary leiomyosarcoma of the inferior vena cava may be related to abnormal function and status of the endocrine system, and the tumor originates from vascular smooth muscle cells of the vein wall, which is a rare malignant tumor. In 1996, Mingoli reported 218 cases in a comprehensive review of the literature. Because of its retroperitoneal location, smooth muscle sarcoma of the inferior vena cava often has an insidious onset and symptoms are related to the size and location of the tumor, with abdominal pain, symptoms of inferior vena cava obstruction, tumor wasting status, and abnormal liver and kidney function. Radical resection of the tumor is the most fundamental and effective treatment, including the involvement of the inferior vena cava and other tissues. In this paper, we report a recent case of smooth muscle sarcoma of the inferior vena cava involving the posterior hepatic segment and the upper and lower renal veins. The patient’s vascular involvement was fully evaluated before surgery and the formation of collateral circulation in the inferior vena cava drainage area was found, so reconstruction of the inferior vena cava and both renal veins was not routinely performed, and the tumor was completely resected together with the inferior vena cava of segments I and II. Case report The patient was a 49-year-old female admitted to the hospital with “swelling of both lower extremities, varicose veins of the abdominal wall for 2 years, and retroperitoneal masses found for 1 week” without abdominal pain and distension, and no significant change in weight. She had no history of hypertension for 2 years, no history of uterine fibroids, and 3 years after undergoing a yin hysterectomy for uterine prolapse. Physical examination revealed coiled worm-like dilated veins in the abdominal wall. Preoperative blood tests, liver and kidney functions, and tumor markers were not abnormal. Evaluation of the urological system: intravenous pyelogram showed a soft tissue density shadow on the right side of the lumbar spine, and the right kidney, right renal pelvis and calyces and right ureter were displaced to the lateral side by compression. Nuclear renal perfusion: glomerular rate filtration (GFR) 68.2 ml/min, right kidney 36.1 ml/min, left kidney: 32.1 ml/min, slightly poor perfusion and function of both kidneys. CT venous angiography suggested: soft tissue density shadow in the inferior vena cava, size 14.5cm×6.6×4.7, the inferior edge started from the beginning of the inferior vena cava, the superior edge reached the posterior hepatic segment, both renal veins were involved, the right renal artery was posteriorly displaced by compression, the duodenum and the head of the pancreas were displaced forward digital subtraction angiography (DSA) suggested: inferior vena cava occlusion, extensive peripheral collateral circulation formation; transrenal artery super-selective renal Venography suggested: bilateral renal veins did not converge into the inferior vena cava, the inferior vena cava was not clearly shown, the left renal vein was indirectly visualized and converged into the hemichoroidal vein, the left genital vein was reversed; the right renal vein was indirectly visualized and converged into the odd vein via the right perinephric vein.