Robot-assisted nephrectomy for retroperitoneal liposarcoma compressing the kidney: a case report with urological management perspective

BACKGROUND: Liposarcoma (LS) is the second most common histological subtype of soft tissue sarcoma, accounting for approximately 7% of all soft tissue sarcomas, among which retroperitoneal liposarcoma (RPLS) is not a rare clinical entity. While RPLS involving the kidney and requiring combined urological management is relatively uncommon with limited clinical reports, it is often asymptomatic in the early stage, with clinical symptoms appearing only when the tumor compresses adjacent organs. Surgical resection is the cornerstone of treatment. CASE PRESENTATION: A 54-year-old female was diagnosed with a well-differentiated giant retroperitoneal RPLS (250 mm × 92 mm) compressing the right kidney via contrast-enhanced MRI. After strict multidisciplinary evaluation in accordance with the 2024 NCCN Guidelines for Soft Tissue Sarcoma, preoperative core needle biopsy was not performed, and the retroperitoneal approach was selected for surgical intervention. On August 6, 2024, Da Vinci Xi Surgical System robot-assisted retroperitoneal tumor resection combined with right nephrectomy and retroperitoneal lymph node dissection was successfully completed via the retroperitoneal approach. Postoperative pathology and immunohistochemistry (MDM2 (+), S-100 (+), etc.) confirmed the diagnosis. The patient recovered uneventfully and was discharged on postoperative day 6 with individualized adjuvant targeted therapy. Follow-up CT scans at 3 months, 6 months, and 1 year postoperatively showed no tumor recurrence, and laboratory examinations such as serum creatinine were normal. This case preliminarily confirms the feasibility and safety of robot-assisted retroperitoneal approach for strictly selected giant RPLS (> 20 cm) confined to the retroperitoneal space, and provides a standardized urological management reference for similar cases. DISCUSSION: Most existing robot-assisted retroperitoneal liposarcoma (RPLS) surgeries are performed via the transabdominal approach, and the reported cases of retroperitoneal approach are limited to moderately sized tumors (diameter < 10 cm). This case demonstrates the feasibility and safety of robot-assisted retroperitoneal approach for giant RPLS (> 20 cm) strictly confined to the retroperitoneal space, expands the application scope of this approach, and provides a standardized urological management strategy for RPLS compressing the kidney for clinical reference.