Renal tubular epithelial (RTE) cells line the renal tubules. RTE cells in urine sediment are more significant than other types of epithelial cells.
An RTE cell is distinguished by its eccentrically placed nucleus. The cells can be round, oval, columnar, or cuboidal. Papanicolaou stain helps distinguish RTE cells from other mononuclear cells in urine. The arrows in the upper image indicate two RTE cells.
Increased numbers of proximal and distal convoluted RTE cells are seen in cases of acute tubular necrosis and specific drug or heavy metal intoxication. Oval fat bodies are RTE cells that have absorbed lipids in the urinary filtrate. Their identity can be confirmed using polarized microscopy and lipid stains. The arrow indicates an oval fat body in the lower image.
