The Impact of Germline BHD Mutation on Histological Concordance and Clinical Treatment of Patients With Bilateral Renal Masses and Known Unilateral Oncocytoma

Abstract

Managing patients presenting with oncocytoma in the setting of bilateral renal masses is a challenging scenario. Nevertheless, pathologic concordance of oncocytic neoplasm in one kidney with tumors in the contralateral kidney is not known. We aim to evaluate the influence of germline Birt-Hogg-Dubé (BHD) mutation on concordance rates to assist in management of these patients. We reviewed records of the NIH patients between 1983 and 2009 having bilateral renal masses, known pathology bilaterally, and presence of oncocytoma or oncocytic neoplasm in at least one kidney. The presence of oncocytoma or oncocytic neoplasm in two renal units was considered concordant. Demographic, pathological and clinical data were collected. The patient population consisted of 40 patients: 23 with BHD and 17 patients without diagnosis of BHD. Patients with BHD were younger (p<0.01) but there were no other differences between two groups. However, patients with BHD had a statistically lower histologic concordance between bilateral masses when compared to patients without the diagnosis of BHD (Fisher's exact test, p<0.01). Additionally, the subgroup of patients (n=8) without BHD who had multifocal renal masses demonstrated 100% oncocytoma concordance between renal units. In patients with bilateral renal masses BHD patients have significantly lower histologic concordance rates compared to patients without BHD. Patients with BHD should be monitored and managed differently than patients without detected genetic mutations, especially those with multifocal oncocytomas. Genetic testing for BHD should be considered in the algorithm for management of patients with bilateral renal masses and known oncocytoma.