Abstract: SA-PO0197
A Rare Case of Cast Nephropathy Secondary to Marginal Zone Lymphoma
Session Information
- Onconephrology: MGRS, HSCT, Electrolytes, RCC, and More
November 08, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Lavu, Narmada, Creighton University, Omaha, Nebraska, United States
- Islam, Imtiaz M., CHI Health Good Samaritan, Kearney, Nebraska, United States
- Mansur, Abeera, CHI Health Good Samaritan, Kearney, Nebraska, United States
Introduction
Cast nephropathy is a cause of acute kidney injury. This report presents a rare case of cast nephropathy caused by lymphoma rather than the more common multiple myeloma.
Case Description
A 77-year-old man with stage IV CKD and a history of hypertension, hyperlipidemia, diabetes, BPH, kidney stones, and marginal zone lymphoma presented with Acute Kidney Injury (AKI) with a rise of creatinine from 1.5 to 2.5 mg/dL over one year. Previously diagnosed with lymphoma via peripheral blood flow cytometry, he had been managed conservatively by his oncologist. On presentation, he had significant proteinuria and an elevated lambda free light chain (3.4 g/L), with otherwise unremarkable glomerulonephritis workup. A CT-guided kidney biopsy was ordered to evaluate suspected cast nephropathy contributing to AKI. While awaiting results, plasmapheresis was initiated to reduce free light chain burden and prevent further kidney injury.
The kidney biopsy ultimately revealed lambda-type light chain cast nephropathy, involvement by low-grade B-cell lymphoma with plasmacytic differentiation, light and heavy chain deposition disease (IgG1 lambda), and severe arteriosclerosis secondary to hypertension.
In coordination with nephrology, the oncologist initiated rituximab and bendamustine due to worsening renal function, anemia, and thrombocytopenia. The patient underwent seven plasma exchanges, reducing serum lambda FLC to 0.3 g/L and creatinine to 2.0 mg/dL.
Discussion
Light chain cast nephropathy results from excess light chains forming obstructive complexes with endogenous tubular proteins like Tamm-Horsfall glycoprotein, causing kidney injury.
Light chain cast nephropathy is most commonly caused by multiple myeloma but can rarely occur in other monoclonal gammopathies, including Waldenstrom's macroglobulinemia, lymphoma, and chronic lymphocytic leukemia. Lambda light chain cast nephropathy in marginal zone lymphoma is extremely rare with only one case report published thus far.
Reducing circulating FLCs supports renal recovery. Cast nephropathy-related AKI is a medical emergency with high dialysis risk and one-year mortality. Prompt diagnosis and treatment of lymphoma are crucial, and clinicians should maintain a broad differential, as cast nephropathy can rarely result from gammopathies and lymphomas beyond multiple myeloma.