Cystic dilatations within the pelvis in patients with ipsilateral renal agenesis or dysplasia

A total of 13 cases of cystic dilatations in the pelvis with ipsilateral renal agenesis or dysplasia was detected during renal ultrasonic mass screenings among 280,000 children within the last 2.5 years. The frequency was approximately 0.00464%. These anomalies included 7 cases of Gartner's cyst and 6 of seminal vesicle cyst. Sonographically, the cystic dilatations displayed a typically cystic nature with no internal echoes. The cysts were located laterally or posteriorly to the bladder, and the cystic mass protruded into or was behind the bladder and sometimes bulged the bladder wall. The dysplastic kidney in the patients with ipsilateral cystic dilatations was not detected by sonography due to its small size and the fact that it was obscured by bowel gas or overlying tissue densities. Three cases of dilated ureter communicating with the cyst were found on sonography. Since ultrasonic examination is an excellent method to identify a fluid-filled cystic structure, ultrasonography has become an important modality in the early detection, diagnosis and followup of these cystic dilatations.