Abstract: FR-PO1292
A Foamy Disguise: Unveiling Monoclonal Gammopathy of Renal Significance in an Autoimmune Multiverse
Session Information
- Onconephrology: Diagnostic Dilemmas, Therapy-Related Toxicities, and Clinical Cases
October 23, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1600 Onconephrology
Authors
- Catahay, Jesus Alfonso, Montefiore Einstein Medical Center, New York, New York, United States
- Kumar, Neelja D., Montefiore Einstein Medical Center, New York, New York, United States
Introduction
Monoclonal gammopathy of renal significance (MGRS) is a group of rare disorders with a prevalence of 0.32% in age >50 in which monoclonal proteins cause kidney damage. It is often underdiagnosed due to its wide overlap with various autoimmune diseases, delaying in diagnosis and treatment. This case presents a diagnostic dilemma of worsening renal function, hematuria, and proteinuria in the context of autoimmune turmoil.
Case Description
50/F with a PMH of Sjogren's syndrome, Rheumatoid arthritis, SLE, MGUS, hypothyroidism, HTN, HLD, CKD (base creatinine 1.4-1.7), who presented for nausea and vomiting. On admission, she was found to have worsening bipedal edema, AKI (peak creatine 3.2), proteinuria (UPCR 13.2g, previously 3.9g in 2025), and microscopic hematuria. No lymphadenopathy on exam. Calcium was low-normal. Concern for Lupus nephritis was raised, given not on DMARD therapy, non-compliance with hydroxychloroquine and prednisone, and lost to follow-up with Rheumatology since 2021.
Serological workup revealed normal complement levels; positive anti-SSA/ro but negative anti-dsDNA, anti-CCP, anti-centromere, anti-GBM, anti-topoisomerase, anti-smith, RF factor, anti-MPO, and anti-PR3. ANA titer was 1:80. SPEP- Kappa light chain 43mg/L, and Lamba light chain 241 mg/L with K/L ratio 0.18. UPEP- 3.5% M-spike IgA lamba light chain clonality. Echo revealed EF 45%. BM biopsy (2020) showed <10% atypical plasma cells. Kidney biopsy demonstrated severe amyloidosis, with lambda light chain clonality and no evidence of lupus nephritis or Sjogren syndrome. Given these findings, MGRS-AL amyloid was identified. Chemotherapy (Dara-CyBorD) was immediately started, and she was followed up as an outpatient.
Discussion
MGRS is a rare and serious but often underdiagnosed condition due to its overlapping presentation with other autoimmune diseases. Left untreated, it progresses to end-stage renal disease (ESRD) due to direct light and heavy chains/immunoglobulin-induced glomerulo-tubulointerstitial injury, and if associated with AL amyloidosis with cardiac involvement, can lead to death. Kidney biopsy establishes the diagnosis and its types. Treatment includes targeting the plasma or B-cell clone with chemotherapy. Renal transplant is considered effective but associated with high recurrence of disease. Early detection is crucial for preventing severe clinical outcomes