Late relapse of IgM nephropathy-associated nephrotic syndrome after repeated administration of immune checkpoint inhibitor against pulmonary adenocarcinoma.

ICPIs were effective for primary and metastatic foci of lung adenocarcinoma, but their repeated use provoked a late relapse of IgM nephropathy and lethal lesions in pancreas and lung. ICPIs should be used carefully in cases of immune-related disease.