Kidney stained with Masson?檚 trichrome, light micrograph. Masson's trichrome method allows a good distinction between proximal and distal convoluted tubules. The light green stain included in this method stains the brush border, allowing the proximal convoluted tubules to be identified. This is a renal cortex in which proximal convoluted tubules predominate, although several distal tubules also appear, with larger lumen, an absence of brush border and a smaller size of the cells compared to the proximal convoluted tubule. In the lower right corner there is a kidney Malpighian corpuscle.