Abstract: FR-PO255
Atypical Presentation of Renal Amyloidosis in a Patient with Plasma Cell Dyscrasia (PCD)
Session Information
- Onconephrology: From AKI to CKD and Everything in Between
November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Sakhuja, Priyal, Stony Brook University Hospital, Stony Brook, New York, United States
- Hennigar, Randolph Alexander, Stony Brook University Hospital, Stony Brook, New York, United States
- Abdulrahman, Rula A., Stony Brook University Hospital, Stony Brook, New York, United States
Introduction
Amyloidosis (AD) is deposition of abnormal proteins that can lead to organ dysfunction. Light chain AD (AL amyloidosis) is the most common systemic form. This is commonly associated with PCDs such as multiple myeloma (MM). This case focuses on a patient with IgA PCD who develops an atypical presentation of renal AD.
Case Description
76-year-old male with hypertension, diabetes, hyperlipidemia, coronary artery disease, heart failure, atrial fibrillation, urinary bladder AD and chronic kidney disease (CKD) was seen at CKD clinic. Cr was 1.8-2.0 mg/dl. Urinalysis with no hematuria, urine protein to creatinine ratio (UPCR) was 621 mg/g. SPEP signified M-spike and immunofixation with IgA-kappa monoclonal protein bands. Patient was referred to hematology. Serum IgA was 952 mg/dL (103-591) with elevated kappa/lambda ratio 4.48 (0.53-1.51). Bone marrow biopsy showed 15-20% plasma cells and was negative for AD. PET CT with no lytic lesions. He was diagnosed with IgA PCD.
MM labs remained stable with no treatment planned. Renal biopsy was indicated to rule out monoclonal gammopathy of renal significance. Urine immunofixation showed monoclonal IgA band and repeat UPCR was 132 mg/g. Biopsy revealed amyloid deposition limited to few glomeruli and arterioles with greater kappa than lambda light chains. Given IgA-kappa paraproteinemia, AL-type amyloidosis was the favored diagnosis.
Discussion
AD has a strong association with PCD. This case highlights an atypical presentation of renal AD which often presents with significant amounts of proteinuria and primarly affect the glomeruli. About 65% of patients with renal AD are afflicted with nephrotic syndrome. When amyloid deposition is found in the tubulointerstitial (TI) compartments, proteinuria is not a common feature. Additionally, lambda light chains are seen more often than kappa light chains as they are more amyloidogenic.
Our case is atypical due to the absence of massive proteinuria and predominance of kappa light chains. Insignificant proteinuria can often be due to deposits confined to the TI or vascular compartments, however our patient had deposits in the glomeruli. Thus, it is important to note that even in the absence of significant proteinuria, a patient with known PCD with renal dysfunction, may still undergo renal biopsy. The histological findings can also vary despite the degree of proteinuria.