Objective: To investigate the relative frequency of idiopathic focal segmental glomerulosclerosis (FSGS) in renal biopsy-proven diseases, and its criteria and significance of clinicopathological diagnosis.
Methods: We reviewed all the inpatients that were diagnosed by renal biopsies from 1990 to 2001, of whom 65 were identified as idiopathic FSGS. Their histological characteristics were analyzed together with their clinical findings.
Results: (1) The incidence of idiopathic FSGS accounted for 2.2% of all the renal biopsies, 3.2% of primary glomerular diseases, and 5.8% of patients with massive proteinuria. (2) The subtypes of idiopathic FSGS were hilar lesion (12.3%), peripheral lesion (23.1%), mixture lesion (60.0%), collapsing lesion (3.1%), and tip lesion (1.5%), which were frequently accompanied by other morphologic variants, such as synechia of Bowman's capsule, podocyte hyperplasia and hypertrophy, segmental endothelial and mesangial proliferation, and interstitial fibrosis, etc. As the sclerotic lesions distributed segmentally and overlapped by other variants, it was difficult to get the correct diagnosis. (3) Most of the patients with segmental endothelial and mesangial proliferation had massive proteinuria.
Conclusion: Idiopathic FSGS was not a common glomerular disease in our study. Podocyte lesion, segmental endothelial and mesangial proliferation may play an important role in the formation of segmental sclerosis in idiopathic FSGS.