In nephrolithiasis , the main pathological changes in the renal tissue are the development of dystrophic, necrobiotic changes in the cortical layer, which is the morphofunctional area of the kidneys, in the epithelia of the glomeruli, increased hydrostatic pressure in the renal plexus, and varying degrees of atrophy due to hemodynamic disorders in the kidneys. The initial changes include hyaline droplet dystrophy in the epithelia of the proximal tubules , condensation of protein substrates in the primary urine in the tubule lumen, condensation of mineral salts in the tubule lumen, and deposition of heavy metal salts and pigments in the renal tubules and calices.