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.