Tubular atrophic lesion, or focal segmental glomerulosclerosis (FSGS), is a common primary glomerular disease in children and adults with nephrotic syndrome (NS). It is characterized histopathologically by segmental glomerular scarring with or without intra-glomerular capillary foam cell formation and adhesions. Focal means that only part of the glomerulus is involved (50% of the glomerulus is involved); segmental means that part of the glomerular lobules are involved; and glomerulosclerosis means staged glassy changes or scarring of the entire glomerulus. Pathological features are mostly associated with tubular atrophy lesions and interstitial fibrosis of the kidney. The following diseases are the causes of tubular atrophy lesions: 1. Membranous nephropathy (membranous nephropathy, MN), also known as membranous glomerulonephritis, is characterized by diffuse immune complex deposition under the epithelial cells of the glomerular basement membrane with diffuse thickening of the basement membrane. The main clinical manifestation is nephrotic syndrome (NS) or asymptomatic proteinuria. 2. Membrano-proliferative glomerulonephritis (MPGN), one of the least common types of glomerulonephritis, is generally divided into primary and secondary. The disease has been known by various names, including mesenteric capillary glomerulonephritis (MCGN), mesenteric capillary proliferative nephritis, lobular nephritis, and hypocomplementemic nephritis. 3. Focal segmental glomerulosclerosis Focal segmental glomerulosclerosis (FSGS) is a common primary glomerular disease in children and adults with nephrotic syndrome (NS), which is characterized histopathologically by glomerular segmental scarring with or without intra-glomerular capillary foam cell formation and adhesions. Focal means that only part of the glomerulus is involved (<50% of the glomerulus is involved); segmental means that part of the lobules of the glomerulus is involved; spherocytosis means that the whole glomerulus is staged with glass-like changes or scar formation. 4, immunosuppressive drug and anticancer drug toxic nephropathy (nephropathy due to poisoning of immunosuppressive drug and anticancer drug) refers to the application of immunosuppressive drugs and anticancer drugs that cause lesions of glomeruli, tubules and interstitium as well as bladder damage.