title: Practical Application of Columbia Classification for Focal Segmental Glomerulosclerosis.
abstract: Focal segmental glomerulosclerosis (FSGS) is a heterogeneous clinicopathological entity. Two frameworks for the classification of FSGS have been described: etiologic and morphologic. The etiologic classification is distinguished among genetic, adaptive, virus-associated, drug-induced, and idiopathic types. Morphologic classification is commonly referred to as the Columbia classification published in 2004, which distinguishes five variants: collapsing, tip, cellular, perihilar, and not otherwise specified (NOS). This classification is based on light microscopic patterns with rigorously defined specific criteria, which can be applied to primary and secondary forms of FSGS, and has been widely used over the past 10 years both as a diagnostic and as a prognostic clinical tool. This paper defines common histopathological features of FSGS, distinguished characters among five variants, and points out the confusion about terminology of variants, because most were proposed in the past with different definitions. Despite good interobserver reproducibility of this classification system, difficulty in its application may arise in the interpretation of lesions with mixed features of more than one variant in the same tissue specimen and with late lesions, because other variants may evolve into the NOS variant over time.
authors.affiliation: Department of Pathology, Kyungpook National University Hospital, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Republic of Korea.
authors.forename: Man-Hoon
authors.initials: MH
authors.lastname: Han
authors.affiliation: Department of Pathology, Yeungnam University College of Medicine, 170 Hyunchung-ro, Nam-gu, Daegu 42415, Republic of Korea.
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
mesh_terms: D001706:Biopsy / Q000592:standards; D005923:Glomerulosclerosis, Focal Segmental / Q000145:classification / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D007668:Kidney / Q000473:pathology*; D008853:Microscopy / Q000592:standards*; D009398:Nephrology / Q000592:standards; D017410:Practice Guidelines as Topic; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D009626:Terminology as Topic