Chylous ascites following surgical treatment for Wilms tumor

Purpose: Postoperative chylous ascites is a rare complication of retroperitoneal surgery that has considerable morbidity. We review the pathogenesis and management of chylous ascites following surgical treatment of Wilms tumor. Materials and Methods: We identified 9 children with chylous ascites after surgical treatment of Wilms tumor. Of these cases 3 were treated at a single institution during the last 20 years and 6 were identified during retrospective chart reviews of patients enrolled in National Wilms Tumor Studies 3 and 4 to identify surgical complications. Chylous ascites presented as increased abdominal girth and poor feeding. Paracentesis or laparotomy was diagnostic. Results: Patient age at presentation with Wilms tumor ranged from 6 to 95 months (median 15). Left nephrectomy was performed in 5 cases, right nephrectomy in 3, and left nephrectomy and partial right nephrectomy in I with bilateral disease. Lymphadenectomy including the hilar and periaortic lymph nodes was performed in 5 patients, 4 of whom also underwent some form of suprahilar lymph node dissection. Three patients underwent lymph node sampling of the hilar, periaortic and some suprahilar lymph nodes. All children received adjuvant chemotherapy and 4 were treated with adjuvant irradiation to the surgical bed before the diagnosis of chylous ascites. The interval between surgery and diagnosis of ascites ranged from 12 to 49 days (median 21). Of the patients 7 were successfully treated with conservative measures, total parenteral nutrition and/or a diet containing primarily medium chain triglycerides, and 2 required invasive procedures, including exploratory laparotomy and ligation of disrupted lymphatic vessels or placement of a peritoneovenous shunt. Conclusions: Extensive lymph node dissection, particularly above the level of the renal hilum, appears to be associated with the development of postoperative chylous ascites. The National Wilms Tumor Study guidelines do not require formal lymph node dissection for staging and only lymph node sampling is recommended. Elimination of formal lymphadenectomy along with meticulous ligation of lymphatics should decrease the incidence of this complication. Fortunately, conservative treatment with total parenteral nutrition and/or medium chain triglycerides will remedy the problem in the majority of children.