has part has part characteristic of has modifier Renal tubular atrophy Atrophic tubules must be distinguished from acute tubular injury as both can show extensive tubular epithelial changes. In acute tubular injury, tubules are often dilated and tubular basement membranes are smooth and maintain normal thickness, in contrast to the contracted tubules with thickened and wrinkled tubular basement membranes of tubular atrophy. Further, in acute tubular injury, tubules are usually back-to-back or mildly separated by interstitial edema, while in tubular atrophy tubules can be separated by interstitial fibrosis. Uniform thickening of tubular basement membranes without shrinkage and otherwise healthy epithelial cells can be seen in diabetic nephropathy. Duplication, or lamellation, thickening, and disruption of tubular basement membranes with tubular dilatation can be seen in medullary cystic kidney disease/nephronophthisis. Abnormal renal tubular epithelial morphology abnormal atrophied nephron tubule