Abstract: FR-PO0481
Kappa Light-Chain Proximal Tubulopathy as a Reversible Renal Manifestation of Indolent Small Lymphocytic Lymphoma
Session Information
- AKI: Case Reports - TMA, Vasculitis, Immune-Mediated Injury, and Systemic Disease
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Dilaver, Ragibe Gulsah, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Bidhan, Sourabh, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Wang, Yihan, Vanderbilt University Medical Center, Nashville, Tennessee, United States
- Sanghani, Neil S., Vanderbilt University Medical Center, Nashville, Tennessee, United States
Introduction
Monoclonal gammopathy-associated kidney disease may lead to progressive renal dysfunction. Kappa light chain proximal tubulopathy (LCPT) is a rare manifestation caused by monoclonal light chain deposition within proximal tubular cells. We present a case of LCPT associated with untreated small lymphocytic lymphoma (SLL) with complete renal recovery after clone-directed therapy.
Case Description
A 78-year-old man with small B-cell lymphoma diagnosed in 2006 was referred in April 2025 for elevated creatinine and proteinuria suspected monoclonal gammopathy. Creatinine increased from a baseline of 1.1–1.2 mg/dL to 1.6 mg/dL. SPEP showed a monoclonal spike with kappa/lambda ratio of 302.3. He was asymptomatic. Bone marrow biopsy demonstrated abnormal lymphoplasmacytic cells with focal amyloid deposition, and flow cytometry showed kappa-restricted B and plasma cells. PET/CT revealed diffuse FDG-avid adenopathy and splenomegaly.
Kidney biopsy in July 2025 demonstrated kappa LCPT and severe arteriosclerosis. Given renal involvement, splenomegaly, thrombocytopenia, and progressive lymphoma burden, treatment with obinutuzumab-based therapy, later combined with bendamustine, was initiated in August 2025. He completed six cycles with excellent response. By January 2026, creatinine normalized and proteinuria resolved. Follow-up PET imaging showed marked improvement.
Discussion
This case highlights that indolent SLL may cause clinically significant monoclonal gammopathy-associated kidney disease despite minimal symptoms and mild creatinine elevation. Kidney biopsy was essential in identifying LCPT and establishing renal involvement as an indication for therapy. Prompt clone-directed treatment resulted in hematologic response and complete renal recovery, emphasizing the importance of early recognition and tissue diagnosis in patients with lymphoproliferative disorders and unexplained kidney dysfunction.