Abstract: SA-PO233
A Rare Case of Crystalglobulin-Induced Nephropathy
Session Information
- Trainee Case Reports - V
October 27, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1203 Glomerular Diseases: Clinical, Outcomes, and Trials
Authors
- Mares, Jon W., Dartmouth Hitchcock Nephrology Fellowship, Hanover, New Hampshire, United States
- Pettus, Jason R., Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
- Brant, Elizabeth J., Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, United States
Introduction
The term monoclonal gammopathy of renal significance (MGRS) describes paraprotein-dependent kidney diseases that do not meet criteria for overt multiple myeloma, including cast nephropathy, Ig deposition disease and amyloidosis. Crystalglobulin-induced nephropathy (CGN), a rare paraprotein-related disease, is most commonly associated with multiple myeloma. We herein report an extremely rare case of CGN associated with MGRS.
Case Description
A 75 year-old man with metastatic prostate cancer and normal renal function presented with anuric AKI requiring dialysis. Serum protein electrophoresis showed 0.3 g/dl IgG kappa monoclonal protein. Serum free κ/λ ratio was 2.3 (ref. 0.5-2.43). ANCA, anti-GBM, hepatitis serologies, rheumatoid factor, C3, C4, and cryoglobulins were normal. Hydronephrosis was not seen on renal ultrasound.
Renal biopsy revealed overt coagulative necrosis (infarction) of 40% of sampled cortical tissue on light microscopy. Abundant PAS-positive crystalline thrombi were present in interlobular arteries, glomerular arterioles and capillaries, and focally extending into proximal tubules. (Fig. 1) Congo red staining was negative. Immunofluorescence showed dim IgG kappa staining in crystalline thrombi. By electron microscopy, crystalline thrombi displayed polygonal and angulated forms with distinctive fine parallel linear organization. Findings confirmed crystalglobulin-induced nephropathy. Bone marrow biopsy was then performed, revealing metastatic prostate cancer without demonstrable multiple myeloma.
His hospital course was complicated by GI bleed and thromboembolic cerebral infarcts. He died 6 weeks after initial presentation upon discontinuing dialysis.
Discussion
CGN is a rare entity usually associated with multiple myeloma, whereas our patient had MGRS. Given a potentially devastating outcome, CGN should be considered in patients presenting with AKI and monoclonal gammopathy.
Fig. 1