Membranous nephropathy and malignancy

Background: There is variable association of membranous nephropathy (MN) with malignancy predominantly of solid organ tumours. There is debate as to how to screen and or investigate for evidence of malignancy in this group. Methods: Retrospective analysis of kidney biopsies performed between 2006 and 2016. Patients with MN were identified and clinical course including age, degree of proteinuria, histology details, treatment and rates of remission documented. Evidence of malignancy and its temporal association with MN noted. Results: Over ten-year period 216 biopsies were performed of which 20 patients (10.8%) had MN [mean age 48.5 years (range 20-82 years); there were to males]. Of these, eight patients (40%) had evidence of malignancy. Four patients were diagnosed with malignancy prior to the biopsy (mean duration 39.7 months) whereas, 4 patients were diagnosed after the biopsy (mean duration 6.7 months). Patients with MN and malignancy were older compared to those without malignancy (63.0 Vs 38.2 years) (P = 0.0054). There was no statistical difference in degree of proteinuria, focal segmental glomerulosclerosis lesions, and number of inflammatory cells in the study population. Conclusions: Higher prevalence (40%) of malignancy was associated with biopsy proven MN from Darling Downs which was statistically significant. Although age appropriate investigations are indicated in these patients, it may be prudent to actively look for evidence of underlying malignancy especially in elderly population given the concerns associated with immunosuppressive therapies.