Despite this measurable frequency of benign tumors, percutaneous renal biopsies are not routinely performed since the incidence of a non-diagnostic result has ranged between 15 and 20%.

In the December issue of the Journal of Urology, Snyder and colleagues from Memorial Sloan-Kettering Cancer Center report on a retrospective institutional review of 815 consecutive patients with surgically treated masses measuring less than 7 cm. Of these patients treated with partial or radical nephrectomy, 16.4% exhibited benign histology. The most common benign histologies were oncocytoma (10.7%), angiomyolipoma (2%), simple or multilocular cysts (1.2%), metanephric adenoma (1%), and cystic nephroma (0.6%). Ten patients (1.2%) were found to have secondary malignancies with a metastasis to the kidney.

As previously reported in the literature, women were twice as likely to exhibit benign histology with a likelihood of 21.4% compared with 13.3% in men (p < 0.002). Interestingly, of all variables evaluated in multivariate analysis including age, presentation, race, and the presence of a cystic component, only gender persisted as an independent predictor of benign histology (hazard ratio = 1.81, 95% CI 1.24 to 2.64, p = 0.002). There was a trend for smaller tumors to be benign (25% of those 1 cm or smaller compared with 10% of those measuring 4-5 cm.), but this was not statistically significant (p = 0.013).

These data suggest that women presenting with renal tumors measuring < 7 cm have double the likelihood of benign histology compared with men, irrespective of tumor size. While the diagnostic accuracy of percutaneous biopsies is insufficient to recommend them in all women presenting with small masses, this study certainly underscores the importance of performing a partial nephrectomy in women whenever technically feasible.

Snyder ME, Bach A, Kattan MW, Raj GV, Reuter VE, Russo P

J Urol. 2006 Dec; 176(6):2391-6

Written by Ricardo Sånchez-Ortiz, MD, a Contributing Editor with UroToday.

Please log-in or register in order to submit comments.

Powered by AkoComment!