[A case of familial juvenile gouty nephropathy associated with a right renal tumor].

We present a case of familial juvenile gouty nephropathy which was associated with a right renal tumor that was found incidentally. The patient was a 27-year-old woman who initially presented with acute gouty arthritis at the age of twenty years. Her mother and her sister had been attacked with acute gouty arthritis in their early twenties. Progressive deterioration in the renal function was noted in the three family members who had experienced gouty attack. Her mother was maintained on hemodialysis. As image diagnoses could not rule out malignancy in her right renal tumor, in situ non-ischemic enucleation of the right renal tumor using a microwave tissue coagulator(Microtaze) and a renal biopsy were performed. The pathological diagnosis of the renal tumor was tubulopapillary adenoma, and the renal biopsy showed minimal change in the glomeruli and tubules. The post-operative course was uneventful. The serum creatinine and creatinine clearance before and three months after the operation were 2.4 mg/dl and 2.6 mg/dl, 36.7 ml/min and 32.5 ml/min, respectively. The renal biopsy findings that glomerular and tubular changes were minimal and there was no tissue precipitation of uric acid or sodium urate, and the fact that her renal function decreased progressively despite the treatment of hyperuricemia suggested strongly that renal function might have deteriorated due to unknown factors other than hyperuricemia.