title: Unique Renal Manifestation of Type I Cryoglobulinemia, With Massive Crystalloid Deposits in Glomerular Histiocytes, Podocytes, and Endothelial Cells.
abstract: OBJECTIVE
  We describe a 62-year-old woman with a 15-year history of a plasma cell dyscrasia (monoclonal IgGκ), manifested by type I cryoglobulinemia and dermal vasculitis.
  
  
  METHODS
  In addition to the clinical examinations, light microscopy with immunohistochemistry, sequential multicolor immunohistochemistry, and electron microscopy were used to characterize the crystalline deposits.
  
  
  RESULTS
  At initial presentation and for a later flare, she was treated with cyclophosphamide and prednisolone with good clinical response. She had renal function decline, microscopic hematuria, and proteinuria. A renal biopsy specimen revealed the presence of glomerular macrophages and duplication of the capillary walls with cellular interposition. Glomerular cells contained abundant needle-shaped eosinophilic crystalline inclusions positive for κ light chain. Electron microscopy confirmed the presence of intracytoplasmatic crystalline structures in endothelial cells, podocytes, and macrophages but not in the tubular epithelium. Rituximab treatment was started. At follow-up (now up to 6 months), renal function remained stable.
  
  
  CONCLUSIONS
  This patient displays a unique renal manifestation of type I cryoglobulinemia related to a plasma cell dyscrasia.
authors.affiliation: From the Departments of Pathology j.j.hoelbeek@amc.uva.nl.
authors.forename: Joris
authors.initials: J
authors.lastname: Hoelbeek
authors.affiliation: Clinical Immunology and Nephrology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Duivenvoorden
authors.affiliation: From the Departments of Pathology.
authors.forename: Onno J
authors.initials: OJ
authors.lastname: de Boer
authors.affiliation: From the Departments of Pathology.
authors.forename: Nike
authors.initials: N
authors.lastname: Claessen
authors.affiliation: From the Departments of Pathology.
authors.forename: Marius A
authors.initials: MA
authors.lastname: Van den Bergh Weerman
authors.affiliation: From the Departments of Pathology.
authors.forename: Joris J T H
authors.initials: JJ
authors.lastname: Roelofs
authors.affiliation: From the Departments of Pathology.
authors.forename: Jesper
authors.initials: J
authors.lastname: Kers
authors.affiliation: Clinical Immunology and Nephrology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
authors.forename: Ineke J M
authors.initials: IJ
authors.lastname: Ten Berge
authors.affiliation: From the Departments of Pathology.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Florquin
mesh_terms: D003449:Cryoglobulinemia / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006644:Histiocytes / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000175:diagnosis* / Q000378:metabolism; D007678:Kidney Glomerulus / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D010265:Paraproteinemias / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D050199:Podocytes / Q000378:metabolism / Q000473:pathology*; D011507:Proteinuria / Q000150:complications / Q000378:metabolism / Q000473:pathology
keywords: Cryoglobulinemia; Crystalloid nephropathy; Crystals; Glomerulopathy