title: Membranoproliferative glomerulonephritis complicating Waldenström's macroglobulinemia.
abstract: BACKGROUND
  Lymphoproliferative disorders causing paraproteinemia can be associated with various kidney injuries including the deposition of monoclonal immunoglobulins (Ig). A known glomerular manifestation of Waldenström's macroglobulinemia is characterized by prominent intracapillary hyaline thrombi and lack of conspicuous glomerular proliferation. The present case was special in 2 aspects: 1. the diagnosis of glomerulonephritis was unexpected before renal biopsy, 2. the prominent glomerular proliferation paired with large intracapillary hyaline thrombi is uncommon in Waldenström's macroglobulinemia-associated glomerulonephritis.
  
  
  METHODS
  A 73-year-old Caucasian woman with a long-standing history of rheumatoid arthritis and Waldenström's macroglobulinemia was admitted for acute renal failure (ARF), which initially was presumed to be the consequence of extrarenal causes. Proteinuria and hematuria were only mild. In renal core biopsy, a membranoproliferative glomerulonephritis (MPGN) and prominent intracapillary hyaline monoclonal IgM thrombi were found in addition to acute tubular necrosis. Of note, the patient's history was positive for purpuric skin changes, suspicious for cryoglobulinemia. However, serological tests for cryoglobulins were repeatedly negative. The ARF resolved before the start of immunomodulatory therapy for Waldenström's macroglobulinemia.
  
  
  CONCLUSIONS
  The presence of MPGN with prominent hyaline thrombi in the context of Waldenström's macroglobulinemia is uncommon and can be oligosymptomatic. We discuss this case in the context of previous literature and classifications suggested for monoclonal Ig-related renal pathologies.
authors.affiliation: Department of Nephrology, University Hospital Essen, University of Duisburg-Essen, Hufelandstr. 55, 45122 Essen, Germany
authors.forename: David
authors.initials: D
authors.lastname: Kratochvil
authors.forename: Kerstin
authors.initials: K
authors.lastname: Amann
authors.forename: Heike
authors.initials: H
authors.lastname: Bruck
authors.forename: Maike
authors.initials: M
authors.lastname: Büttner
mesh_terms: D000368:Aged; D005260:Female; D015432:Glomerulonephritis, Membranoproliferative / Q000150:complications* / Q000175:diagnosis*; D006801:Humans; D008258:Waldenstrom Macroglobulinemia / Q000150:complications* / Q000175:diagnosis*