Differentiation of Renal Oncocytoma from Renal Cell Carcinoma - A Mini-Review

Renal oncocytomas (RO) are the small renal lesions that shared similar histological features with chromophobe renal cell carcinoma (chRCC). There are some hybrid tumors, renal oncocytosis and Brit-Hogg-Dube (BHD) syndrome that have shown the coexistence of both ROs and chRCCs. Presently, most of sporadic cases of ROs and chRCCs have been reported. The majority of ROs and chRCCs patients are asymptomatic, with no significant risk of metastatic ROs compared to chRCCs. However, incidental detection of small renal masses by cross section imaging has constituted an important diagnostic dilemma for their management. Therefore, it is important to differentiation ROs from chRCCs and other subtypes of RCCs for appropriate management. RO is a benign tumor and should be monitored and treated conservatively. For ROs more conservative treatment like nephron-sparing surgery should be considered but we are still on consistent effort of differentiating RO from chRCC. The more accurate diagnosis of ROs remained elusive until modern molecular biomarkers are determined. Even now the standard treatment for small renal tumors remained surgical resection. But recent studies of Cytochrome C oxidase subunit 1 (CCO1) and Tc-MIBI SPECT/CT is appearing valuable in differentiating between these two entities. We suspect that in future the results of these experimental studies will favor us more towards conservative treatment of ROs. This review is focused on the differentiation of renal oncocytoma (RO) from renal cell carcinoma (RCC). It summarizes the introduction, epidemiology, clinical presentation of the renal neoplasms and describes the diagnostic dilemma, pathology, radiology, treatment of the renal neoplasms.