A giant hydronephrotic pelvic kidney mimicking an ovarian cyst in a 34-week pregnancy

Background: A giant hydronephrosis is defined as a dilated pelvi-calyceal system with an amount of urine exceeding one Litre in the urinary tract of an adult. It can mimic several other clinical conditions including a huge ovarian cyst. An ectopic pelvic kidney with hydronephrosis in pregnancy is a rare occurrence. Aim: This study documents a case of giant hydronephrosis that was wrongly diagnosed as an ovarian cyst. Findings: A 36-year old primiparous with a giant hydronephrosis which was initially diagnosed as an ovarian cyst. She was planned for a laparotomy with caesarean section and ovarian cystectomy at 34 weeks gestation. She was delivered of a live female neonate. Further exploration was done which revealed a left ectopic kidney. She had a left simple nephrectomy because the kidney appeared totally unhealthy. Conclusion: There is a need to be careful when dealing with cystic lesions of the abdomen. A high index of suspicion is required and further imaging other than ultrasound scan such as computerized tomography or magnetic resonance imaging may be necessary to make accurate diagnosis. Keywords: Caesarean section, ectopic gestation, hydronephrosis, urinary tract, cystectomy, ovarian cysts