Malignancy is observed in 5-10% of MN in adults , with the risk being highest in patients over the age of 60. A Solid tumor (such as carcinoma of the lung or colon) is most often involved. It is presumed that tumor antigens are deposited in the glomeruli : this is followed by antibody deposition and complement activation , leading to epithelial cell and basement membrane injury and proteinuria due to the associated increase in glomerular permeability. These processes are reversed with removal of the
   tumor , usually leading to gradual remission of the proteinuria.

The malignancy in presumed tumor-induced MN has usually been diagnosed or is clinically apparent at the time at which the proteinuria is noted. The incidence of occult tumor causing MN is less than one to two percent. As a results , a tumor work-up should not be initiated in the absences of some suggestive finding such as unexplained anemia , guaiac positive stools , or weight loss.

The presented patient was a 76 years old man and he was suffering from MN. In the followed studies , the existence of metastatic malignancy was proved.