Chyluria after radiofrequency ablation of renal tumors.
To assess the incidence of chyluria after radiofrequency (RF) ablation of renal tumors and attempt to identify predictors of this phenomenon. Over a 3-year period, 62 consecutive patients with renal tumors were treated by percutaneous computed tomography (CT)-guided or laparoscopic RF ablation, of which 41 underwent at least three posttreatment CT studies and were evaluated in this study. Three radiologists reviewed the pretreatment and posttreatment CT images for the presence or absence of fat-fluid levels in the bladder, the location of the tumor, and the size of the postablation defect. A logistic regression model was used to assess whether ablation defect size or tumor location predicted chyluria. Chyluria was detected at a mean time of 44.5 weeks in 17 (41%) of 41 patients with renal tumors treated by RF ablation. A pretreatment biopsy specimen showed renal cell carcinoma in 74%. Mean tumor size was 2.77 cm, and mean initial ablation size was 4.2 cm. Chyluria persisted in seven patients. Zone of ablation defect size and tumor location were not significant predictors of chyluria (P = .64 and P = .42). Mean follow-up was 77 weeks. Chyluria is a common and asymptomatic finding in a significant proportion of patients undergoing RF ablation for renal tumors. Tumor location and zone of ablation defect size were not predictors of chyluria. The presence of a fat-fluid level should not be mistaken for an air-fluid level.