Secondary Membranous Nephropathy Due to Benign Tumors in 2 Young Women: A Case Report

Membranous nephropathy (MN) is one of the most common causes of adult-onset nephrotic syndrome. We describe the cases of 2 young women in their 20s presenting with nephrotic syndrome due to antiphospholipase A2 receptor (anti-PLA(2)R)-negative MN, that was found to be associated with benign tumors. Both women had no extrarenal symptoms of a connective tissue disease, infection, or malignancy. They both had been previously healthy and were not receiving treatment with any drugs. Both had MN on kidney biopsy. Biopsies were negative for PLA(2)R antigen, and their serum did not demonstrate the presence of anti-PLA(2)R antibodies. Both were investigated for a secondary cause on the basis of negative anti-PLA(2)R serology and biopsy features supportive of secondary MN and were found to have benign tumors on radioimaging: a uterine leiomyoma and mesenteric fibromatosis, respectively. In both instances, the nephrotic syndrome remitted following resection of the tumors. To our knowledge, uterine leiomyoma and mesenteric fibromatosis have not previously been described in association with MN. These cases highlight the importance of pursuing a secondary cause of MN in patients without anti-PLA(2)R antibodies in serum or PLA(2)R antigen on kidney biopsy. (C) 2021 The Authors. Published by Elsevier Inc. on behalf of the National Kidney Foundation, Inc.

Automated summary

Two young women in their 20s with antiphospholipase A2 receptor (anti-PLA(2)R)-negative membranous nephropathy (MN) were found to have benign tumors. Both women had no extrarenal symptoms and were previously healthy. Kidney biopsies showed MN without the presence of anti-PLA(2)R antibodies. Radioimaging revealed uterine leiomyoma and mesenteric fibromatosis in the two cases, respectively. The nephrotic syndrome remitted after tumor resection.