Background: Left paraduodenal hernia (PDH) is a mesenterico-parietal hernia with retroperitoneal retrocolic herniation of the small bowel into a sac formed by a peritoneal fold located near the fourth portion of the duodenum. It’s a rare cause of hydronephrosis by compressed the upper left ureter. Traditionally, PDH are treated by laparotomy.
Case presentation: An 8-year-old boy’s primary purpose was the treatment of cryptorchidism. But hydronephrosis was detected and it was induced by left paraduodenal hernia. Diagnostic laparoscopic exploration confirmed the diagnosis left paraduodenal hernia secondary hydronephrosis. Cryptorchidism was the primary purpose of treatment. The patient was treated with laparoscopic surgery, fixed left paraduodenal hernia, released the ureteropelvic junction obstruction (UPJO) and treated hydronephrosis.
Conclusion: Secondary surgery for treating cryptorchidism would be performed and the long-term follow up was necessary.This case suggests us a rare cause of hydronephrosis in children. Every why has a wherefore. We must pay much attention to any unusual details in our medical work even though these details aren’t related to our primary objects.