Nephrotic syndrome with focal segmental glomerular lesions unclassified by Columbia classification; Pathology and clinical implication

PLoS One. 2021 Jan 5;16(1):e0244677. doi: 10.1371/journal.pone.0244677. eCollection 2021.


Background: The Columbia classification is widely used for diagnosis of focal segmental glomerulosclerosis (FSGS). In practice, we occasionally encounter segmental glomerular lesions unclassified as Columbia classification. We analyzed the clinical implication of unclassified segmental lesions comparing with Columbia-classified FSGS.

Methods: A retrospective cohort study from 13 local hospitals in Japan. From 172 biopsy cases diagnosed with FSGS or minimal change disease (MCD)/FSGS spectrum with unclassified segmental lesions, adult patients with nephrotic syndrome who received immunosuppressive therapies were included. The cases are classified by pathology, i.e., typical FSGS lesions sufficiently classified into subgroups of Columbia classification: collapsing (COL), tip (TIP), cellular (CEL), perihilar (PH), and not otherwise specified (NOS), and unclassified by the Columbia classification into three subgroups: "endothelial damage,"; "simple attachment,"; and "minor cellular lesion,". The response to immunosuppressive treatment and 30% decline of eGFR were compared.

Results: Among 48 eligible cases, all were Japanese, 34 were typical FSGS; 13 TIP, 15 CEL, 6 NOS, and no COL or PH cases. Fourteen were unclassified cases: endothelial damage (n = 6), simple attachment (n = 5), and minor cellular lesion (n = 3). The median age of overall patients was 60 years old and the median of eGFR and urinary protein creatinine ratio was 51.5 mL/min/1.73m2 and 7.35, respectively. They received similar therapeutic regimen. Kaplan-Meier analysis revealed no significant difference in treatment response between typical FSGS and unclassified cases. Evaluating among the subgroups, endothelial damage, simple attachment and minor cellular lesion showed similar treatment response to TIP or CEL. No significant difference was also observed in the 30% decline of eGFR.

Conclusions: Japanese adult patients with nephrotic syndrome showing unclassified segmental lesions as Columbia classification may be equivalent clinical impact as Columbia classification of FSGS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Biopsy
  • Female
  • Humans
  • Immunosuppressive Agents / therapeutic use
  • Japan / epidemiology
  • Kidney Glomerulus / drug effects
  • Kidney Glomerulus / pathology*
  • Male
  • Middle Aged
  • Nephrotic Syndrome / diagnosis
  • Nephrotic Syndrome / drug therapy
  • Nephrotic Syndrome / epidemiology
  • Nephrotic Syndrome / pathology*
  • Retrospective Studies
  • Treatment Outcome


  • Immunosuppressive Agents

Grants and funding

This study was supported in part by a Grant-in-Aid for Intractable Renal Diseases Research, Research on Rare and Intractable Diseases, Health and Labor Sciences Research Grants from the Ministry of Health, Labor, and Welfare of Japan (H29-nanchi-ippan-017.); Japan Agency for Medical Research and Development (18ek0109354h0001.); a fund from Chugai Pharmaceutical Co. However, the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.