[The so-called megaureter-megacystis syndrome: a case report].

We encountered a patient with megaureter-megacystis syndrome showing a giant bladder and dilated ureters with marked reflux, which is very rare; to our knowledge, only 2 patients have been reported in Japan. The patient was a 4-year-old boy, who showed inborn polyposia and polyuria, and proteinuria at the age of 1 year. He visited the pediatric department in our hospital complaining of cold-like symptoms, stomachache and diarrhea. Urinary infection and kidney dysfunction were observed, and the patient was hospitalized for close examination. Bilateral pyelocaliceal hydronephrosis was detected by ultrasonography, and the patient was referred to our department. CT revealed bilateral hydronephrosis (right atrophic kidney), hydroureters and megacystis. Bilateral grade V vesicoureteral reflux, an increase in the bladder volume (> 300 ml), and urination without residual urine were noted by voiding cystourethrography. Uroflowmetry revealed that maximum flow rate was 21.6 ml/sec, voided volume was 110 ml, and residual volume was 24 ml. From these examinations, the patient was diagnosed as having megaureter-megacystis syndrome, and underwent antireflux operation of the bilateral ureters using Cohen's procedures.