Idiopathic collapsing glomerulopathy: A clinicopathologic analysis of 30 cases

Collapsing Glomerulopathy: A Review by the Collapsing Brazilian Consortium

Collapsing glomerulopathy (CG) is a clinicopathologic entity characterized by segmentar or global collapse of the glomerulus and hypertrophy and hyperplasia of podocytes. The Columbia classification of 2004 classified CG as a histological subtype of focal segmental glomerulosclerosis (FSGS). A growing number of studies have demonstrated a high prevalence of CG in many countries, especially among populations with a higher proportion of people with African descent. The present study is a narrative review of articles extracted from PubMed, Medline, and Scielo databases from September 1, 2020 to December 31, 2021. We have focused on populational studies (specially cross-sectional and cohort articles). CG is defined as a podocytopathy with a distinct pathogenesis characterized by strong podocyte proliferative activity. The most significant risk factors for CG include APOL1 gene mutations and infections with human immunodeficiency virus and severe acute respiratory syndrome coronavirus 2. CG typically presents with more severe symptoms and greater renal damage. The prognosis is notably worse than that of other FSGS subtypes.

Collapsing Glomerulopathy: A Single Centre Clinicopathologic Study of Seven Years

INTRODUCTION

Collapsing Glomerulopathy (CG) is recognized as distinct pattern of proliferative parenchymal injury with poor response to empirical therapy.

AIM

A single center retrospective study was carried out to find out clinicopathological features of idiopathic CG.

MATERIALS AND METHODS

A total of 3335 native renal biopsies were analyzed retrospectively which were performed from 2008 to 2014 with emphasis on clinicopathological correlation and histopathological presentation.

RESULTS

Idiopathic CG constituted 0.75% incidence (25 out of 3335 biopsies) of all biopsies, adults constituting major study part with 88%. The duration of the symptoms at the time of biopsy was 34.12±26.09 days and 35±22.91 days respectively in adults and children. Hypertension was noted in 9(40.9%) and oliguria in 8(36.4%) in adults. Urinalysis revealed microscopic haematuria 12(54.5%) in adults. Nephrotic range proteinuria was reported in 10 (45.5%) adult patients. Glomerular collapse with hyperplasia/ hypertrophy of podocytes was seen in 4.54±3.11 glomeruli. Tubular microcystic dilation was seen in 16(64%) patients. Tubular atrophy involving mild (t1) in 15(60%), moderate (t2) in 4(16%) and severe (t3) in 6(24%) patients. Interstitial fibrosis was mild (i1) in 17(68%), moderate (i2) in 2(8%) and severe (i3) in 6(24%) patients.

CONCLUSION

Idiopathic CG is a morphological pattern of grave podocyte injury with poor prognosis. However, there are chances of remission/ recovery if the tubular atrophy and interstitial fibrosis are of grades ≤ t1 i1.