关键词: 足细胞内陷性肾小球病, 临床病理特点, 电镜

Abstract: Objective: Podocyte infolding glomerulopathy (PIG) is a rare glomerular disease, with evidence mainly from case reports and limited large⁃sample studies. This study aims to improve the understanding of this entity and highlight the diagnostic value of electron microscopy (EM). Methods: We conducted a single⁃center retrospective case series of 52 PIG patients diagnosed by renal biopsy at the First Affiliated Hospital of Zhengzhou University between January 2017 and December 2024. Clinicopathological features at biopsy were analyzed, with comparisons between immune complex (IC)⁃positive and IC⁃negative subgroups, and correlations of EM types/severity with proteinuria and treatment response were evaluated. Results: The onset age clustered at 20-59 years, with female predominance (78.85%). Nephrotic syndrome occurred in 55.77%, and 76.92% had autoimmune diseases [71.15% met systemic lupus erythematosus (SLE) criteria]. The detection rate of PIG among all native renal biopsies was 0.11%. IC deposition was present in 76.92%; this group showed more prominent mesangial proliferation, endocapillary proliferation, and crescents (P<0.05), but no differences in loop necrosis, glomerulosclerosis, tubulointerstitial or vascular lesions, nor in age, proteinuria, albumin, or creatinine. Electron microscopy classified PIG into three types: Type A (podocyte infolding) in 5.77%, Type B (microstructures+infolding) in 76.92%, and Type C (microstructures only) in 17.31% of cases; 46.15% were classified as severe. Although Type B and severe PIG demonstrated higher complete remission rates, neither the classification nor the degree of lesion showed statistically significant associations with proteinuria or treatment response. Conclusion: PIG has low incidence, frequently associates with SLE, and often coexists with IC deposition. EM remains the cornerstone for diagnosis and differential diagnosis.