Nephrotic syndrome, renal failure, and renal malignancy: an unusual tumor-associated glomerulonephritis

The association between malignancy and glomerular disease has been appreciated for over three decades. Although the relationship between membranous glomerulonephritis or minimal-change nephrotic syndrome and carcinoma or lymphoma, respectively, are the most widely known, several other glomerular lesions have been described in patients with malignancy. In this article, a patient who presented with nephrotic syndrome, volume overload, and renal failure, who was subsequently found to have a renal mass, is described. Resection of the mass, which proved to be a renal cell carcinoma, led to resolution of proteinuria and improvement of renal function. Pathology on the noninvolved portion of the kidney revealed a membranoproliferative glomerular lesion, a lesion usually associated with lymphomas and not previously described with renal carcinoma. Although a role of tumor antigens and anti-tumor antibodies in producing glomerular immune deposits has been speculated upon, the evidence for this assertion was spotty. However, reports of remission of proteinuria after tumor treatment or removal support a role of tumor products in pathogenesis. Although the association between proteinuria and malignancy is rare, it should be kept in mind, particularly in older patients with membranous glomerulonephritis where the possibility of malignancy needs to be further evaluated.