title: Acute kidney injury with cryoglobulinemic peritubular neutrophilic capillaritis.
abstract: BACKGROUND
  Neutrophil predominant capillaritis and interstitial inflammation is an uncommon renal biopsy finding, with a broad differential diagnosis.
  
  
  METHODS
  A 77-year-old woman presented with a complicated history including vasculitis, cryoglobulinemia, malaise, and systemic symptoms, which progressed to acute kidney injury. Renal biopsy demonstrated prominent neutrophilic capillaritis with interstitial inflammation, and fibrinoid deposits in medullary capillaries and interstitium. Glomeruli showed membranoproliferative glomerulonephritis, but no crescents or necrosis.
  
  
  CONCLUSIONS
  We interpret the capillary and interstitial changes as evidence of cryoglobulin-associated vasculitis, and discuss the differential diagnosis of this uncommon histologic pattern of renal pathology, including other vasculitides, infection, ischemia-infarction, collagen vascular disease, and antibody-mediated allograft rejection, among others.
authors.affiliation: Department of Pathology, Oregon Health Science University, Portland, OR 97239, USA. troxellm@ohsu.edu
authors.forename: M L
authors.initials: ML
authors.lastname: Troxell
authors.forename: D V
authors.initials: DV
authors.lastname: Shackleton
authors.forename: P
authors.initials: P
authors.lastname: Raguram
authors.forename: D C
authors.initials: DC
authors.lastname: Houghton
mesh_terms: D058186:Acute Kidney Injury / Q000473:pathology*; D000368:Aged; D002196:Capillaries / Q000473:pathology; D003449:Cryoglobulinemia / Q000473:pathology* / Q000628:therapy; D005260:Female; D006801:Humans; D007668:Kidney / Q000098:blood supply / Q000473:pathology*; D014657:Vasculitis / Q000473:pathology*