Malignancy-associated membranous nephropathy: focus on diagnosis and treatment

BACKGROUND: The clinicopathological features of malignancy-associated membranous nephropathy have been described previously, but information about diagnosis and treatment remains limited. METHODS: Patients with malignancy-associated membranous nephropathy in a tertiary hospital in China between June 2012 and October 2021 were retrospectively reviewed. RESULTS: Forty-two patients with malignancy-associated membranous nephropathy were identified. Compared to patients with idiopathic membranous nephropathy, patients with malignancy-associated membranous nephropathy were older and less frequently showed glomerular phospholipase A2 receptor staining (37.9% vs 85.0%) and IgG4 predominant deposition (66.7% vs 95.0%). At diagnosis of membranous nephropathy, the malignancy was unknown in 67% (28/42) of patients and was detected only by tumor screening. Among the 19 patients with concurrent diagnosis of cancer and biopsy-proven membranous nephropathy, 15 received anticancer treatment alone initially. Six of the 10 patients who attained cancer remission achieved remission of membranous nephropathy, while none of the 5 patients without remission of cancer did, suggesting a causal relationship between the two diseases. Some patients with persistent or relapsing membranous nephropathy following cancer remission achieved remission of membranous nephropathy after immunosuppressive therapy. Over a median follow-up of 24 months, 25% (10/40) of patients died, mainly due to neoplasia. CONCLUSIONS: Tumor screening is important in patients with membranous nephropathy, especially in elderly patients and patients with negative phospholipase A2 receptor or non-IgG4 predominant deposition. Remission of membranous nephropathy can be observed following remission of cancer in some cases. Immunosuppressive therapy may be considered if membranous nephropathy does not remit after remission of cancer.