Abstract: SA-PO197
Beyond Plasma Cell Disorders: Monoclonal Gammopathy of Renal Significance with Marginal Zone Lymphoma
Session Information
- Onconephrology: Immunological Cross-Talk
November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Bilen, Yara, Cleveland Clinic, Cleveland, Ohio, United States
- Mehdi, Ali, Cleveland Clinic, Cleveland, Ohio, United States
- Bartolomeo, Korey, Cleveland Clinic, Cleveland, Ohio, United States
- Herlitz, Leal C., Cleveland Clinic, Cleveland, Ohio, United States
- Sohail, Mohammad Ahsan, Cleveland Clinic, Cleveland, Ohio, United States
Introduction
Monoclonal Gammopathy of Renal Significance (MGRS) is well recognized with pre-malignant plasma cell disorders. We report a case of MGRS with nephrotic range proteinuria and rapid loss of kidney function in the context of Marginal Zone Lymphoma (MZL).
Case Description
A 65-year-old man with diabetes mellitus and heart failure is admitted for progressive kidney dysfunction. He has chronic kidney disease, baseline creatinine (Cr) 1.5mg/dL, presumably due to diabetes. On presentation, Cr was 2.1mg/dL. Urinalysis with 2+ proteins and 11-25 RBCs/HPF. 24h urine collection revealed proteinuria at 3.5g. 12.5cm kidneys of normal parenchymal thickness and echogenicity were noted on US with no hydronephrosis. Further workup showed C3 56mg/dL (nl: 86-166) and C4<2mg/dL (nl: 13-46). Serum monoclonal testing revealed a low-grade IgM kappa M protein at 0.09g/dL and a free light chain kappa to lambda ratio of 4.04 (nl: 0.26-1.65).
A kidney biopsy showed membranoproliferative glomerulonephritis and IgM kappa restricted deposits. Serum cryoglobulins resulted as positive, type II with a monoclonal IgM Kappa and polyclonal IgG. IgM Cryoglobulin resulted at 17mg/dL with IgA and IgG cryoglobulin at 3 and 19mg/dl respectively. A clinico-pathologic diagnosis of cryoglobulinemia related MPGN was thus made. A bone marrow biopsy unmasked an underlying lymphoproliferative disorder consistent with MZL. CT imaging showed borderline diffuse adenopathy. As such, patient was started on Rituximab, Cytoxan, Vincristine and Prednisone. His kidney function worsened requiring dialysis. Despite cryoglobulins clearance, he remains dialysis dependent while on therapy for his MZL at four months post-diagnosis.
Discussion
Despite an improvement in recognition, MGRS remains a foreign entity both in the nephrology and hematology spheres. It is frequently thought of in the context of plasma cell neoplasms. This case illustrates an MGRS case occurring with an underlying B-cell clone and manifesting as MPGN with progressive kidney dysfunction and nephrotic range proteinuria. A high index of suspicion and a low threshold for kidney biopsy are key to making the diagnosis. As in this case, the kidney biopsy might be the only clue to the underlying lymphoma and a crucial diagnostic step with paramount therapeutic implications, both for kidney and overall patient survival.