Abstract: SA-PO0793
Cryoglobulinemic Glomerulonephritis in MYD88-Negative Waldenström Macroglobulinemia
Session Information
- Glomerular Diseases: Lupus Nephritis, Monoclonal Gammopathy-Related Disease, and Transplantation
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Al Assaad, Rami, University of South Florida, Tampa, Florida, United States
- Audi, Akram, University of South Florida, Tampa, Florida, United States
Introduction
Cryoglobulinemic glomerulonephritis (GN) is a rare renal manifestation of lymphoplasmacytic lymphoma/Waldenström macroglobulinemia (LPL/WM). We present a case of MYD88-negative LPL/WM presenting manifesting as nephritic syndrome and biopsy-proven cryoglobulinemic membranoproliferative GN.
Case Description
A 61-year-old man with history of embolic stroke status post patent foramen ovale repair, hypertension, and non-melanoma skin cancers was evaluated for worsening renal function, nephrotic-range proteinuria, uncontrolled hypertension, and progressive lymphocytosis. He had persistent lymphocytosis since 2018 with prior flow cytometry demonstrating a monoclonal CD20+, CD23+, CD5-, CD10- B-cell population. while MYD88 mutation testing was negative. In late 2025, he developed uncontrolled hypertension, foamy urine, anemia, and acute kidney injury. Serum creatinine increased from baseline 1.1–1.3 mg/dL to 1.5–1.7 mg/dL. Urine protein increased to 5 g/day from 1.9 g/day with microscopic hematuria. positive cryoglobulins, low C3/C4 levels, positive cold agglutinins, SPEP with serum IFE showed IgM kappa band but the monoclonal component was too slight to form an M spike. Bone marrow biopsy showed low-grade B-cell lymphoma with plasmacytic differentiation favoring LPL/WM with ARID1A mutation and absent MYD88 mutation. PET/CT demonstrated no hypermetabolic lymphadenopathy. The patient received weekly rituximab for four doses with subsequent negative cryoglobulins, stable renal function. Kidney biopsy later demonstrated membranoproliferative GN with pseudothrombi consistent with cryoglobulinemic GN and 25% interstitial fibrosis/tubular atrophy.In April 2026, urine protein was 0.8g/day, resolution of microscopic hematuria, better controlled hypertension and improvement in serum creatinine.
Discussion
Renal disease occurs only in 3% of WM patients. Kidney biopsy plays a major role in making the correct diagnosis. This case highlights cryoglobulinemic GN as a renal manifestation of MYD88-negative (wild-type) WM. Although MYD88-negative WM is generally a more aggressive lymphoma, our patient had an indolent hematologic disease and absence of significant systemic tumor burden, but he developed severe nephritic syndrome secondary to cryoglobulinemic GN, which required prompt therapy. Rituximab-based therapy resulted in marked improvement supporting the pathogenic role of the underlying clonal B-cell disorder.