Diagnosis of non

As up to 25% of renal neoplasms may be benign, renal function preservation is often a priority in the management of small renal masses. Studies have demonstrated the occurrence of non-neoplastic renal diseases in nephrectomy specimens, but this has not been studied in the setting of renal mass biopsy. Therefore, we conducted this study to determine the feasibility of evaluating the non-neoplastic renal parenchyma in such a limited tissue sample. We identified 117 needle biopsies for renal lesions in adults from the Department of Pathology archives (2007–2017). Additional stains for periodic acid–Schiff or Jones methenamine silver were obtained as needed. Of 117 cases, non-neoplastic renal parenchyma was absent in 91 cases (78%) and present in 26 cases (22%). Review of the hematoxylin and eosin slides identified 6 cases (5%) with significant diffuse and/or nodular mesangial sclerosis. Additional review of the periodic acid–Schiff and Jones’ stains demonstrated two cases that showed diffuse and focally nodular mesangial sclerosis that was consistent with diabetic nephropathy. The needle biopsy is increasingly useful in guiding the management of patients with small renal masses. Although less than 25% of renal mass biopsies had sufficient non-neoplastic renal parenchyma for pathologic evaluation, medical renal diseases, such as diabetic nephropathy, could be diagnosed. On the contrary, the biopsy specimens for urothelial lesions rarely yield sufficient adjacent non-neoplastic renal parenchyma for pathologic evaluation