Department of Nephrology，Second Xiangya Hospital， Central South University；Institute of Nephrology，Changsha 410011，China

Objective To analyze the clinical and pathological characteristics of renal amyloidosis, to decrease the chance of misdiagnosis and missed diagnosis, and to improve the diagnosis accuracy and the therapeutical effect.MethodsWe retrospectively analyzed the clinical and pathological data of 20 patients with renal amyloidosis，who were hospitalized in the Second Xiangya Hospital from Jan. 2005 to Aug. 2009 and were diagnosed as renal amyloidosis by renal biopsy. ResultsOf the 20 patients， 19（95%） were over 40 years old, 55% patients suffered more than 2 systems injuries, and 80% patients displayed the typical nephrotic syndrome. Brickred homogeneous amyloid deposition could be seen in glomerular mesangial cell and capillary membrane loop after HE staining as well as in the interstitials, the blood vessels, and the tubular wall. Eighteen patients were AL type and potassium permanganate test was positive. Another 2 were AA type and potassium permanganate test was negative. The pathological characteristics of AL type was similar to that of AA type. Immunoglobulin light chain κ and λ could be detected in AL type but not in AA type.Conclusion Renal amyloidosis is common in elderly patients. The clinical manifestations of renal amyloidosis are not always specific. It could be made the final diagnosis through examining the typical pathophysiolgical changes by renal biopsy combined with Congo red staining. Suspected patients should be performed with renal biopsy and Congo red staining as soon as possible to avoid misdiagnosis and missed diagnosis.