Histopathological Evaluation of Non-Neoplastic Renal Parenchyma Adjacent to Tumors in Partial Nephrectomy Specimens of Renal Cell Carcinoma

Abstract

Purpose: The optimal margin for partial nephrectomy of renal cell carcinoma (RCC) has not been clearly defined. We investigated the viability of glomeruli and tubules in non-neoplastic renal parenchyma adjacent to tumors and analyzed the predictive factors that affect them.Materials and Methods: Data were gathered retrospectively from 64 patients who underwent partial nephrectomy for RCC between January 2008 and December 2011. We evaluated glomerular viability of non-neoplastic renal parenchyma adjacent to tumors using H&E staining and tubular viability was assessed by Klotho stain. Each renal unit was assigned a RENAL nephrometry score using preoperative imaging. We also investigated the correlation between RENAL score, estimated glomerular filtration rate (GFR) and glomerular and tubular viability.Results: The percentage of non-viable glomeruli was higher in the region within 2-mm from the tumor compared with the region＞2-mm from the tumor. The mean non-viable tubular distance from the tumor was 1.36±0.597mm. Only the correlation between glomerular non-viability (%) within 2-mm from the tumor and non-viable tubular distance (mm) was significant. Correlations between RENAL score and glomerular non-viability in the region ≤2- mm from the tumor and non-viable tubular distance were not significant for all RENAL factors. But, glomerular non-viability 5-10-mm from the tumor was inversely correlated with preoperative estimated GFR.Conclusions: Regardless of RENAL nephrometry scores, the viability of glomeruli and tubules within 2-mm from RCC was affected by tumor mass, and that ＞5-mm from the tumor was affected by subclinical comorbidities. These may suggest new guidelines of RCC management intraoperatively and postoperatively.