Pre-existing non-neoplastic renal diseases or lesions may influence patient renal function after tumor removal. However, its description is often neglected or omitted in pathologic reports. To determine the incidence and clinical significance of non-neoplastic lesions, we retrospectively examined renal tissues obtained during 85 radical nephrectomies for renal cell carcinoma.

One paraffin-embedded tissue block from each case containing a sufficient amount of non-tumorous renal parenchyma was cut and processed with hematoxylin and eosin and periodic acid-Schiff methods. Non-neoplastic lesions of each histological compartment were semi-quantitatively and quantitatively evaluated.

Among the various histologic lesions found, tubular atrophy, arterial intimal thickening, and glomerulosclerosis were the most common (94.1%, 91.8%, and 88.2%, respectively). Glomerulosclerosis correlated with estimated glomerular filtration rate at the time of surgery, as well as at 1- and 5-years post-surgery (p=.0071), but tubulointerstitial fibrosis or arterial fibrous intimal thickening did not. Post-hoc analysis revealed that glomerulosclerosis of more than 20% predicted post-operative renal function. However, its significance disappeared when gender and age were considered.

In conclusion, non-neoplastic lesions, especially with regard to glomerulosclerosis percentage, should be described in pathology reports to provide additional information on renal function decline.