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Abstract: PO2197

Myeloma Cast Nephropathy with Diffuse Amyloid Casts: Two Case Reports and Literature Review

Session Information

  • Onco-Nephrology - 2
    October 22, 2020 | Location: On-Demand
    Abstract Time: 10:00 AM - 12:00 PM

Category: Trainee Case Report

  • 1500 Onco-Nephrology

Authors

  • Yong, Zihao, Renal Division, Department of Medicine, Peking University First Hospital; Institute of Nephrology, Peking University; Renal Pathology Center, Institute of Nephrology, Peking University; Key laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China;, Beijing, China
  • Xiaojuan, Yu, Renal Division, Department of Medicine, Peking University First Hospital; Institute of Nephrology, Peking University; Renal Pathology Center, Institute of Nephrology, Peking University; Key laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China;, Beijing, China
  • Wang, Su-xia, Renal Division, Department of Medicine, Peking University First Hospital; Institute of Nephrology, Peking University; Renal Pathology Center, Institute of Nephrology, Peking University; Key laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China;, Beijing, China
  • Zhao, Ming Hui, Renal Division, Department of Medicine, Peking University First Hospital; Institute of Nephrology, Peking University; Renal Pathology Center, Institute of Nephrology, Peking University; Key laboratory of Renal Disease, Ministry of Health of China; Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China;, Beijing, China
Introduction

Multiple myeloma (MM) is a plasma cell derived hematologic malignant disease. The malignant proliferating plasma cells can secrete massive monoclonal immunoglobulins which can cause various pathologic types of renal injury. Myeloma cast nephropathy (MCN) is the most common pathologic lesion with the worst renal prognosis. Rarely, the free light chains in the protein casts can form amyloid fibrils. Here, we report two rare cases of myeloma cast nephropathy with diffuse amyloid casts.

Case Description

Case 1: A 54-year-old Chinese man presented with a 4-year history of multiple myeloma, proteinuria and hematuria. He had Monoclonal IgAλ plus free λ spike in both serum and urine. He was treated with chemotherapy. His serum creatinine was normal until 11 months before admission, and he was on hemodialysis 1 month before admission. Renal biopsy showed diffuse amyloid casts in the tubular lumens, and he had no obvious amyloid deposits in other kidney compartments and no sign of extra-renal amyloidosis. The amyloid fibrils formed around mononuclear cells which were CD68 negative. The patient was maintained on chemotherapy and hemodialysis, and he died 8 months after renal biopsy.
Case 2: A 58-year-old Chinese man presented with a one-and-a-half-year history of proteinuria and slowly rising serum creatinine. He had Monoclonal IgDλ spike in both serum and urine. Amyloid casts were observed in the tubular lumens and in the centre of some casts were mononuclear cells. There were no amyloid deposits in other kidney compartment and no sign of systemic amyloidosis. The patient also had fine granular deposits along the tubular basement membrane with λ linear staining along tubular basement membrane suggesting light chain deposition disease. The patient was treated with bortezomib-based followed by lenalidomide-based chemotherapy and achieved very good partial remission (VGPR). After twenty-seven months of follow-up, the patient still had no sign of systemic amyloidosis.

Discussion

These 2 cases of MCN with diffuse amyloid casts have different pathologic characteristics from the usual myeloma casts and tubular epithelial cells may play important roles in the pathogenesis.