Background: The oncologic safety of blunt tumor enucleation (TE) of renal cell carcinoma (RCC) depends on the presence of a continuous pseudocapsule (PS) around the tumor and on the possibility of obtaining negative surgical margins (SMs). Objective: To investigate the PS and SMs after TE to define the real need to take a rim of healthy parenchyma around the tumor to avoid the risk of positive SMs. The risk of PS invasion related to other clinical and pathologic variables was also evaluated. Design, setting, and participants: Between September 2006 and December 2007, data were gathered prospectively from 187 consecutive patients who had kidney surgery. Overall, 90 consecutive patients who had TE for RCC were eligible for the study. All specimens were evaluated using an image analyzer by a dedicated uropathologist. Intervention: TE was done by blunt dissection using the natural cleavage plane between the tumor and the normal parenchyma. Measurements: PS,SM, and routinely availableclinical andpathologic variableswere recorded.