Complete Resolution of Paraneoplastic Membranous Nephropathy Following Curative Therapy of Triple-Negative Breast Cancer

A paraneoplastic syndrome, which includes glomerulopathy, is a manifestation of malignancy unexplained by direct tumor burden. Membranous nephropathy (MN) may be associated with malignancies that are primarily solid tumors of the lung, prostate and gastrointestinal tract. It is rarely associated with breast cancer. To our knowledge, we herein report the first case of MN associated with triple-negative carcinoma of the breast. The patient initially presented with MN as a paraneoplastic nephrotic syndrome. Treatment resulting in a complete pathological response of the breast cancer also resolved the MN. Neither has recurred after a 48-month follow-up. The patient exhibited autoantibodies against phospholipase A2 receptor and was also antinuclear antibody (ANA) and anti-Smith (anti-Sm) antibody positive. These results suggest that the neoplasm evoked an autoimmune response, which resolved with treatment. ANA and anti-SM positivity closely correlated with the neoplasm activity supporting this hypothesis.