Paraneoplastic proteinuria in papillary renal cell carcinoma; a case report.

We report a 55-year-old man presented with anemia and weakness, history of flank pain, hematuria and nephrotic syndrome. Spiral abdominopelvic computerized tomography (CT) scan showed multiloculated cystic mass (120 ×100 ×80 mm) in lower portion of left kidney with internal enhancing solid components and coarse peripheral calcifications. Radical nephrectomy of left kidney was done and biopsy confirmed renal cell carcinoma (RCC), papillary type, sarcomatoid foci, Fuhrman grade III. We assumed that, presence of nephrotic syndrome and paraneoplastic glomerulopathy leaded to heavy proteinuria in this case. Secondary, paraneoplastic glomerulopathy such as immunoglobulin A nephropathy and focal segmental glomerulosclerosis as a paraneoplastic syndrome of RCC have been reported previously. RCC can present with a wide range of signs and symptoms. Atypical presentations of papillary RCC such as proteinuria should be considered for patients presenting with nephrotic syndrome.