Abstract: TH-PO639

Nephrotic Syndrome as First Presentation of Waldenstrom’s Macroglobulinemia

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Author

  • Chauhan, Ayushi, University of Connecticut, Hartford, Connecticut, United States
Background

Waldenstrom’s macroglobulinemia (WM) is a disorder characterized by bone marrow (BM) infiltration by a lymphoplasmacytic lymphoma and a serum immunoglobulin M (IgM) paraprotein. In contrast to multiple myeloma, renal involvement is uncommon in WM with nephrotic syndrome (NS) being rare. Here we describe a case of NS as a first presentation of WM.

Methods

83-year-old male with a history of hemorrhagic stroke and hypertension presented for evaluation of anasarca. He reported worsening bilateral lower extremity, scrotal and penile edema over 4 weeks. He also felt “slowed down” and noted vision changes and gait instability. Lab values yielded the following: Hemoglobin 9.5, hematocrit 28.2, WBC 6.9 and platelets 282. BUN/creatinine (Cr) was 29/0.8. ESR was markedly elevated at 101. Urinalysis showed a bland sediment and more than 300 mg/dL protein without casts. Urine protein excretion was 5188 mg/g Cr. Serum protein electrophoresis showed significant hypoalbuminemia with a gamma region spike consistent with the presence of a monoclonal protein: IgM >3150, IgA 32 and IgG <108. Serum and urine immunofixation showed monoclonal IgM lambda (λ) and Bence-Jones proteinuria, respectively. λ free light chains were elevated at 13.10 with the Kappa/ λ ratio 0.19. β-2 microglobulin was 4.1. Serum viscosity and complement (C3 and C4) levels were within normal limits and cryoglobulins were negative. A subsequent BM biopsy revealed near effacement of marrow by diffuse interstitial B-Cell infiltrate and a positive MYD88 mutation indicative of WM. A kidney biopsy was not performed and no cancer-targeted therapy was initiated as the patient elected comfort focused care.

Conclusion

Diagnosis of WM-associated nephropathy is of immense clinical import due to its prognostic impact. Biopsy-proven WM nephropathy is associated with shortened overall survival especially in those with renal function decline despite treatment. Pathology can be variable however light-chain amyloidosis usually causes NS in WM. Despite presence of Bence-Jones proteinuria, as in our case, cast nephropathy is less culpable due to low quantity of the light chains. Reports are also emerging on minimal change disease as a paraneoplastic manifestation of WM with resultant NS. Regardless of mechanism of nephropathy, treatment of the underlying WM with chemoimmunotherapy, especially Rituximab, has largely shown to result in NS resolution.