IgA nephropathy in IgG kappa multiple myeloma.

Multiple myeloma (MM) frequently affects kidney function through multiple mechanisms. Nonetheless, some patients develop kidney injury due to other causes. A 54-year-old woman was diagnosed with IgG kappa MM developed IgA nephropathy without cast nephropathy. Further studies did not show criteria for MM progression or other causes. This case highlights the need for further investigation of kidney injury in MM patients (such as toxicity of previous drugs, infectious events, or immune-mediated disorders).