Abstract: PO1922
Monoclonal Gammopathy of Renal Significance: Not Reserved for the Elderly
Session Information
- Cancer-Related Kidney Injury: Paraneoplastic Syndromes and More
November 04, 2021 | Location: On-Demand, Virtual Only
Abstract Time: 10:00 AM - 12:00 PM
Category: Onco-Nephrology
- 1500 Onco-Nephrology
Authors
- Balakrishnan, Suryanarayanan, Saint Vincent Hospital, Worcester, Massachusetts, United States
- Martin, Suzanne Gwen, Saint Vincent Hospital, Worcester, Massachusetts, United States
Introduction
Monoclonal gammopathy of renal significance (MGRS) is defined by renal involvement of monoclonal immunoglobulins in the absence of other organ involvement. MGRS includes a wide variety of renal lesions. It is particularly important to distinguish MGRS from monoclonal gammopathy of undetermined significance (MGUS), as early treatment improves renal survival.
Case Description
36F with a history of pre-eclampsia, stage II chronic kidney disease, and hypertension well-controlled on valsartan 320 mg and metoprolol succinate 100 mg, presented 2 years postpartum with worsening hypertension and proteinuria. Initial urinalysis was positive for 3+ proteinuria and 2+ blood, with dysmorphic RBCs on sediment. Urine protein to creatinine ratio (UPC) was 1574 mg/g Cr. ANA and ANCA were negative, and complements were normal. Her creatinine rose from 1.2mg/dL to 1.8mg/dL over the next two years, and proteinuria rose to 4.7 g/d. Renal biopsy confirmed IgG kappa monoclonal immunoglobulin deposition disease, with large subepithelial deposits and moderate tubular injury, with 20% global and segmental glomerulosclerosis, 10% interstitial fibrosis and tubular atrophy, and moderate vascular sclerosis. Serum and urine immunofixation and serum free light chain ratio were normal. Bone marrow biopsy was also negative, confirming the diagnosis of MGRS. She was treated with dexamethasone and bortezomib for a year, followed by lenalidomide, with stabilization of her renal function and proteinuria for over 3 years. Her creatinine is 2.4mg/dL and UPC is 354mg/g Cr. She has been off therapy for 4 months with no change.
Discussion
There has been historical resistance to treat MGRS, as it does not meet criteria for a proliferative disorder and chemotherapy toxicity is of concern. However, it is associated with progression to CKD/ESRD without treatment. Treatment depends on renal pathology and clone type, and may include proteasome inhibitors, alkylating agents, or immunomodulators. Certain forms of MGRS, such as AL amyloidosis, may benefit from autologous hematopoietic stem cell transplantation due to its high rate of recurrence. Her young age is an unusual feature of MGRS. This case highlights the need for renal biopsy in patients with worsening proteinuria and renal function out of proportion to hypertension, and the role of chemotherapy in MGRS to change the trajectory of disease.