Abstract: TH-PO640

Lambda Light Chain Tubulopathy in Waldenstrom’s Macroglobulinemia

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • De Leon, Joseph, Harbor-UCLA Medical Center, Torrance, California, United States
  • Kommana, Sandhya L, Harbor ULCA MEDICAL CENTER, Harbor City, California, United States
  • Dukkipati, Ramanath B., Harbor-UCLA Medical Center, Torrance, California, United States
Background

Light Chain Tubulopathy is typically seen in Plasma cell dyscrasias such as Multiple Myeloma, however it has been reported in Waldenstrom’s Macroglobulinemia. The vast majority of cases involve the Kappa Light Chains, with Lambda Light Chains being exceedingly rare.

Methods

A 63 year old female with untreated Waldenstrom’s Macroglobulinemia was admitted for decreased oral intake resulting into acute kidney injury(AKI). She has not had definitive treatment due to absence of absolute indications such as cytopenias, organomegaly, hyperviscosity symptoms and nephropathy until 2 months prior to admission, when she had a rising creatinine of 1.6 mg/dl (baseline 1.3) and opted not to get the treatment of Rituximab. She presented on admission with AKI with creatinine of 3.9 mg/dl, trace proteinuria, 2-3RBC/HPF and FeNa<1%. She was volume repleted to manage the pre renal state although the possibility of plasmacytoma related kidney injury remained high. Unexpectedly, her kidney function did not have robust improvement and she eventually underwent kidney biopsy, the strongest suspicion being immune mediated MPGN. Pathology revealed renal involvement by atypical lymphoplasmacytic infiltrate with λ-light chain restriction with inclusions within proximal tubular epithelial cells with crystalloid appearance consistent with λ-light chain tubulopathy.

Conclusion

Waldenstrom’s Macroglobulinemia have circulating monoclonal IgM proteins in association with a B cell lymphoproliferative disorder. Renal involvement occurs in < 5% of patients with varied pathology including direct invasion of renal parenchyma by neoplastic lymphoplasmacytic cells, intraglomerular occlusive thrombi of the IgM paraprotein and in some, development of MPGN with associated type I or type II cryoglobulinemia. Light chain proximal tubulopathy (LCPT) is characterized by cytoplasmic inclusions of monoclonal light chains within proximal tubular cells. One study focused on pathologic features of 40 cases of crystalline LCPT from 2000-2014 all of which showed κ-restriction. The incidence of LCPT is typically seen in Multiple Myeloma and has been reported in Waldenstrom’s Macroglobulinemia. The vast majority of reported cases of LCPT are κ-restricted. The finding of LCPT, from Waldenstrom’s Macroglobulinemia, with λ-light chain restriction makes this case exceedingly rare and to our knowledge, never been reported.