Bilateral renal masses: pathologic concordance and impact of temporal presentation

The aim of this paper was to evaluate the pathologic concordance of bilateral renal masses and the influence of synchronous or asynchronous occurrence on patient long term survival.

Thirty-one consecutive patients with bilateral synchronous (N.=17, 55.0%) or asynchronous (N.=14, 45.0%) renal masses were retrospectively reviewed from January 2000 to December 2010. We included all patients with confirmed diagnosis on pathologic examination of a specimen or a percutaneous biopsy and evidence of angiomyolipoma on CT. Survival was assessed using the Kaplan-Meier method. RESULTS. The first lesion was larger than the second (60 vs. 30 mm, P<0.001). Pathologic concordance rate between tumors was 87.1%. A clear cell carcinoma was associated with a papillary carcinoma in 3.2%, and an angiomyolipoma in 6.4%. Median time of occurrence of a metachronous lesion was 50 months (IQR: 24; 92). Disease-free survival at 5 and 10 years was 87.2% and 78.5%. No statistical difference in disease free survival was observed between synchronous and metachronous tumors. conclusion: Discordant pathology between bilateral renal masses is uncommon, with a slight probability of benign tumor. Occurrence of a metachronous tumor can exceed 10 years.