Abstract: FR-PO0707
Atypical Presentation of EXT1/EXT2 Membranous Nephropathy
Session Information
- Glomerular Diseases: Membranous Nephropathy, FSGS, and Podocytopathies
October 23, 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
- Nieves Santiago, Richard Alexis, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
- Peleg, Yonatan A., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
Introduction
EXT-1 and EXT- 2 positive membranous nephropathy remains a rare form of MN accounting for 5-10% cases. It is most associated with autoimmune diseases, particularly SLE. These cases to be presented are particularly notable given the rarity of EXT-1 and EXT-2 MN, further compounded by an atypical presentation in an uncommon patient demographic.
Case Description
First Case: A 60 y/o M with history of mantle cell NHL s/p R-Hyper-CVAD/MA immuno-chemotherapy 07/2005-09/2005 and RTX 2006-2013 c/b hypogammaglobulinemia, recurrent sinus infections, and chronic DVT on Coumadin who presented to clinic for evaluation of subacute nephrotic syndrome in 02/2023. No evidence of systemic autoimmune symptoms were identified. Serum, urine studies, treatment and biopsy results are summarized in table 1.
Second Case: A 64 y/o M with history significant for factor V Leiden s/p IVC filter, T2DM, HTN, diverticulosis with partial colon resection, COVID-19 (3/2021, 1/2022), lymphedema (for 10 years), and HFpEF who presented to the ER on 04/2022 for lower extremity edema; found to have acute right posterior tibial DVT, and nephrotic syndrome. Patient also had AKI, SCr 2.33mg/dL from baseline of 1.44mg/dL. No evidence of systemic autoimmune symptoms were identified. Serum, urine studies, treatment and biopsy results are summarized in table 1.
Discussion
The clinical significance of these cases lie in the presence of +EXT1/EXT-2 membranous nephropathy in an atypical patient demographic. Most cases in the literature for EXT-1 and EXT-2 MN involve younger female patients with clinical manifestations of autoimmune disease. In contrast, these cases are unique as both were older males with renal limited lupus MN, representing an uncommon presentation of this disease. Additionally, these cases highlight how this population showed positive outcomes similar to what has been reported in EXT-1/EXT-2 positive cases compared to EXT-1/EXT-2 negative lupus MN patients and their successful achievement of remision.
Table 1