Renal Hilar Lesions: Biological Implications for Complex Partial Nephrectomy.

ABSTRACT

OBJECTIVE: To perform a comprehensive histopathologic review of sporadic resected solitary cT1 renal masses comparing those with and without radiographic involvement of the hilum. MATERIALS AND METHODS: A prospectively maintained database was queried for all cT1 renal masses undergoing resection classified per the R.E.N.A.L. nephrometry score. Hilar masses were defined as tumors that abut the main renal artery or vein on cross-sectional imaging. Demographic, treatment, renal mass, and histopathologic characteristics were compared between hilar and nonhilar renal masses. Multivariate regression model analyses were performed to assess factors associated with renal mass upstaging and disease recurrence. RESULTS: A total of 1324 stage 1 renal masses met criteria for analysis of which 226 (17.1%) were defined as hilar. Hilar masses were larger, scored with higher complexity, and more likely to undergo a radical nephrectomy. On histopathologic analysis, we found no difference between hilar and nonhilar masses regarding the incidence of malignancy, presence of high nuclear grade, or risk of upstaging. On multivariate analysis, a tumor's hilar location was not associated with upstaging or disease recurrence. CONCLUSION: We present a comprehensive histopathologic review of a large cohort of cT1 hilar lesions noting no difference in the risk of malignancy, high nuclear grade, upstaging, or recurrence when compared to nonhilar lesions. Together, these data suggest that there is no compelling cancer-specific rationale to perform a radical nephrectomy when managing renal hilar tumors.