RENAL-FAILURE DUE TO TUBULAR OBSTRUCTION BY LARGE PROTEIN CASTS IN PATIENTS WITH MASSIVE PROTEINURIA

We describe two patients with nephrotic syndrome whose histologic find ings on renal biopsy and at autopsy are characterized by numerous larg e protein casts in dilated cortical tubules, as well as podocyte swell ing with effacement of foot processes in the glomeruli. Both patients progressed rapidly to renal failure. The casts and the protein precipi tate in the Bowman's capsule were found to be composed of varying prop ortions of albumin and globulin but contained no Tamm-Horsfall protein . This suggests a glomerular rather than tubular origin of proteins. L ight and electron microscopic examination of tubules revealed changes mainly due to compression by the casts. We propose that tubular obstru ction due to the large casts was the main cause of renal failure.