Renal cell carcinoma presenting as nephrotic syndrome.

A 64-year-old woman presenting with a history of increasing oedema was found to have nephrotic syndrome with a 24-hour urinary protein excretion of 20.7 g and renal impairment with an initial serum creatinine level of 197 mumol/l (2.16 mg/dl). A renal tumour was demonstrated by ultrasound scanning and subsequent nephrectomy revealed a renal carcinoma extending as far as the resected end of the renal vein. Histology of the kidney not involved by the tumour showed normal light microscopic appearances, with electron microscopy demonstrating foot process fusion, suggesting a diagnosis of minimal-change nephropathy. Nephrotic syndrome is a rare complication of renal cell carcinomas, and it is particularly uncommon for minimal change nephropathy to be associated with solid tumours.