title: Atypical anti-glomerular basement membrane disease.
abstract: BACKGROUND
  Anti-glomerular basement membrane (anti-GBM) disease classically presents with aggressive necrotizing and crescentic glomerulonephritis, often with pulmonary hemorrhage. The pathologic hallmark is linear staining of GBMs for deposited immunoglobulin G (IgG), usually accompanied by serum autoantibodies to the collagen IV alpha-3 constituents of GBMs.
  
  
  METHODS
  Renal pathology files were searched for cases with linear anti-GBM to identify cases with atypical or indolent course. Histopathology, laboratory studies, treatment and outcome of those cases was reviewed in detail.
  
  
  RESULTS
  Five anti-GBM cases with atypical clinicopathologic features were identified (accounting for ∼8% of anti-GBM cases in our laboratory). Kidney biopsies showed minimal glomerular changes by light microscopy; one patient had monoclonal IgG deposits in an allograft (likely recurrent). Three patients did not have detectable serum anti-GBM by conventional assays. Three patients had indolent clinical courses after immunosuppressive treatment. One patient, untreated after presenting with brief mild hematuria, re-presented after a short interval with necrotizing and crescentic glomerulonephritis.
  
  
  CONCLUSIONS
  Thorough clinicopathologic characterization and close follow-up of patients with findings of atypical anti-GBM on renal biopsy are needed. Review of the literature reveals only rare well-documented atypical anti-GBM cases to date, only one of which progressed to end-stage kidney disease.
authors.affiliation: Department of Pathology , Oregon Health & Science University , Portland, OR , USA.
authors.forename: Megan L
authors.initials: ML
authors.lastname: Troxell
authors.affiliation: Department of Pathology , Oregon Health & Science University , Portland, OR , USA.
authors.forename: Donald C
authors.initials: DC
authors.lastname: Houghton
keywords: Goodpasture's; anti-glomerular basement membrane disease; crescentic glomerulonephritis