The impact of germline BHD mutation on histological concordance and clinical treatment of patients with bilateral renal masses and known unilateral oncocytoma.

PURPOSE: Managing oncocytoma in the setting of bilateral renal masses is a challenging scenario. Nevertheless, to our knowledge the pathological concordance of an oncocytic neoplasm in 1 kidney with tumors in the contralateral kidney is not known. We evaluated the influence of germline Birt-Hogg-Dubé mutation on concordance rates to assist in managing these cases.
MATERIALS AND METHODS: We reviewed the records of patients at the National Institutes of Health between 1983 and 2009 who had bilateral renal masses, known pathology bilaterally and oncocytoma or an oncocytic neoplasm in at least 1 kidney. Oncocytoma or an oncocytic neoplasm in 2 renal units was considered concordant. Demographic, pathological and clinical data were collected.
RESULTS: The population consisted of 40 patients, including 23 with and 17 without a diagnosis of Birt-Hogg-Dubé syndrome. Patients with the syndrome were younger (p <0.01) but there were no other differences between the 2 groups. However, patients with the syndrome had statistically lower histological concordance between bilateral masses than patients without the diagnosis (Fisher's exact test p <0.01). Also, the 8 patients without Birt-Hogg-Dubé syndrome who had multifocal renal masses showed 100% oncocytoma concordance between renal units.
CONCLUSIONS: Of patients with bilateral renal masses those with Birt-Hogg-Dubé syndrome have significantly lower histological concordance than those without the syndrome. Patients with Birt-Hogg-Dubé syndrome should be monitored and treated differently than those without detected genetic mutations, especially patients with multifocal oncocytomas. Genetic testing for Birt-Hogg-Dubé should be considered in the treatment algorithm of patients with bilateral renal masses and known oncocytoma.