Abstract: SA-PO0826
Clinicopathologic Comparison of Fibrillary Glomerulonephritis and AL Amyloidosis: A Single-Center Experience
Session Information
- Glomerular Diseases: Management, Evolving Strategies, and Practice-Changing Advances
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
- Arabi, Ziad, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Tawhari, Mohammed Hadi, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Alreshidi, Ahmed Abdullah, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
- Khormi, Abdullah Hassan, King Abdulaziz Medical City in Riyadh, Riyadh, Riyadh Province, Saudi Arabia
Background
Fibrillary GN and AL amyloidosis are rare causes of proteinuric kidney disease characterized by the presence of organized deposits in the kidney biopsy.
Differentiating these two entities is important step in the management
Methods
This retrospective study included patients with biopsy-proven fibrillary GN or AL amyloidosis at our center between 2017 and 2026.
Clinical presentation, laboratory results, biopsy findings, treatment, and renal outcomes were analyzed.
Results
Out of 1,127 native kidney biopsies performed during the study period, a total of 10 patients were identified: 5 with fibrillary glomerulonephritis and 5 with AL amyloidosis.
Patients with Fibrillary GN more commonly presented with hematuria, Hypertension, and C3- dominant immunofluorescence staining.
Electron Microscope revealed randomly arranged nonbranching fibrils measuring 10 to 20nm, and Congo red staining was negative in all fibrillary GN cases. DNAJB9 immunostaining was positive in 2 patients.
Among AL amyloidosis patients’ Monoclonal light-chain restriction was demonstrated in 80% of AL Amyloid patients, with systemic involvement, and Congo red positivity was present in all the AL amyloid patients. Electron microscopy revealed smaller fibrils measuring 6-11nm. Hematologic evaluation demonstrated plasma cell dyscrasia in 80% of AL amyloidosis patients.
Nephrotic-range proteinuria was present in 80% and 60% of fibrillary and AL amyloid respectively. Progression to kidney failure requiring dialysis occurred in 40% of both groups during follow up period.
Conclusion
Fibrillary GN and AL amyloidosis share overlapping clinical and pathological features, representing important diagnostic challenges. Congo red staining, fibril size on electron microscopy, monoclonal protein evaluation, and DNAJB9 immunostaining are essential for accurate diagnosis and appropriate management.