Renal biopsy findings in Iran: case series report from a referral kidney center

Several registries and single centers have reported the results of their renal biopsies from different parts of the world. As there are only few data regarding the epidemiology of glomerulonephritides in Iran, this study was conducted to determine the results of renal biopsy findings during the last 10 years in our center. Data from 1,436 patients who had undergone a renal biopsy in our center between 1998 and 2007 were collected retrospectively for the first 989 patients and prospectively for the rest of them, including demographic data, renal syndrome at presentation and laboratory findings. All kidney specimens were studied with light and immunofluorescent microscopies. Among 1,407 patients with a definite pathologic diagnosis, 1,052 (74.8%) had a primary glomerular disease, 241 (17.2%) had a secondary glomerular disease, 66 (4.6%) had tubular disease, 19 (1.3%) had vascular disease and 7 (0.5%) had end-stage kidney disease. The most frequent types of biopsy-proven renal diseases were membranous glomerulopathy (MG) (377 patients, 26.8%), IgA nephropathy (IgAN) (155 patients, 11%), lupus nephritis (155 patients, 11%), focal segmental glomerulosclerosis (141 patients, 10%) and minimal change disease (117 patients, 8.3%). The predominant presentation was nephrotic syndrome in almost all cases, with the exception of chronic glomerulonephritis, acute tubular necrosis and acute tubulointerstitial nephritis. The epidemiology of our renal biopsy findings was similar to reports from most European countries and United Arab Emirates, but different from many other neighboring countries, North America and Far East. In our report of 1,407 renal biopsy specimens, MG and IgAN were the most frequent biopsy-proven renal diseases. FSGS was the third cause of primary glomerular disease, and lupus nephritis was the most common secondary glomerular disease. The unusually high frequency of presentation as nephrotic syndrome may be due to referral nature of our center and less liberal indications for renal biopsy.