Background <p>Retroperitoneal lymphatic malformations (LMs) are rare, and their deep location adjacent to critical structures renders treatment particularly challenging. This retrospective study aims to investigate the safety and efficacy of laparoscopic polidocanol foam sclerotherapy (LPFS) in the treatment of retroperitoneal LMs in children.</p> Methods <p>We conducted a retrospective analysis of 12 pediatric patients with retroperitoneal LMs who underwent LPFS at our institution between July 2020 and July 2025. The procedure involved laparoscopic-guided cyst puncture, aspiration, and injection of polidocanol foam prepared using the Tessari technique. Key outcomes included operative details, number of treatment sessions, complications, and treatment response defined by imaging.</p> Results <p>All 12 patients were successfully completed laparoscopically without conversion to open surgery. The cohort comprised 2 macrocystic and 10 mixed LMs, with a median maximum diameter of 8.6&#xa0;cm (range: 5.3–19.3&#xa0;cm). Intracystic hemorrhage was noted intraoperatively in 9 cases and adhesions in 5 cases. Complete radiologic resolution was ultimately achieved in all patients. 10 patients required only a single treatment session, while the remaining 2 achieved complete resolution after a second LPFS session. All ten patients who presented with preoperative symptoms reported complete and sustained resolution. No major complications, such as vascular injury, visceral organ damage, or clinical evidence of adhesion-related obstruction, were observed. During a median follow-up of 36 months (range: 7–60 months), there were no cases of recurrence.</p> Conclusion <p>LPFS is a safe and effective minimally invasive treatment for pediatric retroperitoneal lymphatic malformations. It may represent a feasible option, particularly for lesions in anatomically complex locations.</p>