Kidney, Renal Tubule - Dilation

Renal tubule dilation may occur anywhere along the nephron or collecting duct system. It may occur in focal areas or as tracts running along the entire length of kidney sections (Figure 1).

Renal tubule dilation may occur from xenobiotic administration, secondary mechanisms, or an unknown pathogenesis (see Kidney - Nephropathy, Obstructive ) (Figure 2). Dilation may result from direct toxic injury to the tubule epithelium interfering with absorption and secretion (Figure 3). It may also occur secondary to renal ischemia or from prolonged diuresis related to drug administration. Secondary mechanisms of tubule dilation may result from lower urinary tract obstruction, the deposition of tubule crystals, interstitial inflammation and/or fibrosis, and chronic progressive nephropathy (Figure 4). A few dilated tubules may be regarded as normal histologic variation.