Clinical features and outcomes of adult primary retroperitoneal lymphangioma: insights from a high-volume sarcoma center

Background: Adult primary retroperitoneal lymphangioma (RPL) is an exceptionally rare benign vascular malformation. This study aims to elucidate the clinical presentation, imaging characteristics, management strategies, and long-term outcomes of this condition. Methods: We conducted a retrospective analysis of our prospectively maintained retroperitoneal tumor database at Peking University International Hospital (2014-2024). Inclusion criteria comprised adults (≥18 years) undergoing initial surgical resection with pathological RPL confirmation. Patients with other malignancies or recurrent disease were excluded. Comprehensive follow-up was performed to assess outcomes. Results: Among 28 enrolled patients (13 males, 15 females; median age 31 years), clinical presentation included incidental discovery (42.9%), abdominal discomfort (42.9%), lumbago (10.7%), and lower limb pain (3.6%). Preoperative imaging assessment was performed using Ultrasonography (US) (82.1%), computed tomography (CT, 100.0%), and magnetic resonance imaging (MRI, 14.3%). Characteristic CT findings typically included thin-walled multiloculated cystic masses with septal enhancement. All patients achieved R0/R1 resection, with 18 open and 10 laparoscopic procedures (2 conversions). Major complications occurred in 10.7% of cases (lymphatic leakage: 2; pancreatic fistula: 1), all resolving with appropriate management. Histopathological and immunohistochemical analysis confirmed lymphatic differentiation (D2-40: 100%; CD31: 89.3%; CD34: 84.6%). During median follow-up of 76 months, no recurrences or disease-specific mortality were observed. Conclusions: RPL represents a rare benign tumor frequently presenting with nonspecific symptoms. Complete surgical resection demonstrates excellent safety and long-term efficacy, with individualized approach selection based on tumor characteristics. Our findings from this substantial Chinese adult cohort provide valuable insights for managing this uncommon condition.