Ascites is common in patients with liver cirrhosis. It may present as a clinical manifestation in nephrotic syndrome in adults, typically with heart- or liver disease together with other oedema. We describe a 64-year-old male patient - with no liver or heart disease - with relapsing ascites and no other oedema, who was surprisingly diagnosed with primary membranous nephropathy (MN), and the autoantibody anti-PLA2R was positive. Through immunotherapy the ascites disappeared. Anti-PLA2R and anti-TSHD7A can be used in the diagnosis (primary/secondary MN) and may play a role in the treatment and prognosis.