Nephrotic syndrome as a result of membranous nephropathy caused by renal cell carcinoma

A 77‐year‐old woman was admitted for a renal biopsy to evaluate a case of nephrotic syndrome. In the course of the examination, a right renal tumor was incidentally found. We performed a right radical nephrectomy in advance of the renal biopsy. Histologically, the tumor was diagnosed as a renal cell carcinoma (clear cell carcinoma) and the non‐neoplastic renal cell tissue showed membranous nephropathy (MN). After surgery, the nephrotic syndrome remitted without any further medical treatment and the MN was considered to be a malignancy associated syndrome. There have been few case reports in the literature regarding this association and we wish to describe another case.