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 accompanied by tubular atrophy lesions and interstitial fibrosis. Pathological characteristics: ① segmental: one or several glomeruli sclerosis, the rest of the glomeruli normal; ② focal: a glomerular partial sclerosis; ③ mostly accompanied by tubular atrophy, interstitial fibrosis; ④ can be combined with MCD; ⑤ can be combined with MsPGN. According to domestic statistics, thylakoid proliferative nephritis (thylakoid glomerulonephritis) is the most frequent, followed by focal segmental glomerulosclerosis, membranoproliferative nephritis, and membranous nephropathy.