Published online Oct 6, 2019. doi: 10.12998/wjcc.v7.i19.3055
Peer-review started: April 15, 2019
First decision: August 1, 2019
Revised: August 14, 2019
Accepted: August 27, 2019
Article in press: August 27, 2019
Published online: October 6, 2019
Monoclonal immunoglobulin can cause renal damage, with a wide spectrum of pathological changes and clinical manifestations without hematological evidence of malignancy. These disorders can be missed, especially when combined with other kidney diseases.
A 61-year-old woman presented with moderate proteinuria with normal renal function. She was diagnosed with IgA nephropathy combined with monoclonal gammopathy of undetermined significance after the first renal biopsy. Although having received immunosuppressive treatment for 3 years, the patient developed nephrotic syndrome. Repeated renal biopsy and laser microdissection/mass spectrometry analysis confirmed heavy chain amyloidosis. After nine cycles of bortezomib, cyclophosphamide and dexamethasone, she achieved very good partial hematological and kidney responses.
Renal injury should be monitored closely in monoclonal gammopathy patients without obvious hematological malignancy, especially in patients with other pre-existing renal diseases.
Core tip: Monoclonal immunoglobulin can cause renal injury without hematological evidence of malignancy. These disorders can be missed, especially when combined with other kidney diseases. We present a patient initially diagnosed with IgA nephropathy and monoclonal gammopathy of undetermined significance (MGUS). Atypical characteristics and treatment refractoriness of IgA nephropathy led to a second renal biopsy. Amyloidosis was revealed, and laser microdissection/mass spectrometry was used for typing. The patient improved well after therapy containing bortezomib. Renal involvement should be monitored closely in patients with MGUS, especially in those with pre-existing kidney diseases.