Background
Membranous glomerulonephritis (MGN) is rarely associated with necrotising and crescentic glomerulonephritis (NCGN).

Methods
We report the clinical and pathological findings in 15 patients with MGN and NCGN associated with ANCA, anti-GBM or anti-PLA2R antibodies.

Results
The cohort consisted of 15 patients: 7 males and 8 females with a median age of 63 years (range 18-79). In 12/15 patients MGN and NCGN were diagnosed at the time of the biopsy and in 3 cases MGN predated the NCGN. ANCA was positive in 7 cases (6 MPO-ANCA and 1 PR3 –ANCA), anti-GBM antibodies were detected in 5 cases and anti-PLA2R antibodies were found in 2 cases. One case was negative for all antibodies. Microscopic haematuria was present in all but one patient who was anuric and median urinary protein/creatinine ratio (uPCR) was 819.5mg/mmol [range 88-5600]. Pathologic evaluation revealed MGN and NCGN with crescents involving 28% of glomeruli (median, range 5-100%). Follow up was available for all 15 patients; all were treated with steroids; 10 with cyclophosphamide and 6 also received rituximab. At a median follow up of 72 months, 9 had stabilisation or improvement of renal function, 6 patients progressed to ESRD and 4 died during the follow up period.

Conclusions
MGN with crescents associated with ANCA or anti-GBM antibodies is a rare dual glomerulopathy. Patients present with heavy proteinuria, microscopic haematuria and acute kidney injury and should be treated for a rapidly progressive glomerulonephritis. Prognosis is variable and 40% of patients progress to ESRD.