Excretion of Hippuran into Acquired Renal Cysts in Chronic Hemodialysis Patient

Isao Ishikawa, MD, Division of Nephrology, Department of Internal Medicine, Kanazawa Medical University, Uchinada, Kahoku, Ishikawa 920-02 (Japan) Dear Sir, Acquired renal cystic disease (ARCD) is becoming important because of its complications such as bleeding and renal cell carcinoma [1–3]. These cysts are considered to originate mainly from proximal tubular epithelium, based on analysis of the chemical composition of cyst fluid [4,5] and the immuno histochemical examination [6,7]. We examined the excretion of Hippuran, a substance handled by glomerular filtration and tubular secretion, into the acquired cysts 20 and 100 min after intravenous injection in 2 patients. The 1st patient, a 64-year-old man on hemodialysis fo 13 years, underwent right-side nephrectomy because o ARCD complicated with renal cell carcinoma on June ∏ 1985. Twenty minutes before nephrectomy (renal arter clamping) 70 μCi of 131I Hippuran were administers intravenously, and the blood was drawn at the tim of artery clamping. Serum isotopic counts wer 4,730 cpm/ml and the counts in four cysts were 270, 332 420 and 427 cpm/ml in 1.3,1.7,1.0 and 1.5 ml of cyst Ωuic respectively (table 1). Therefore, the cyst fluid/serur ratio of Hippuran was 0.06–0.09 20 min after the adminis tration.