Lumbar pseudomeningocele causing hydronephrosis.

Background/Objective: Pseudomeningocele is most commonly the result of a rent in the meninges during spine surgery. Noniatrogenic causes exist but are rare. Pseudomeningoceles may heal spontaneously, but they may also slowly enlarge. They rarely present as a mass within the abdomen. The objective of this study was to present the first case report of hydronephrosis secondary to lumbar pseudomeningocele. Design: Single case report and literature review. Methods: Single case report. Results: This man had undergone extensive lumbar spine surgery for pain and spondylolisthesis. He subsequently developed a pseudomeningocele that caused hydronephrosis of the left kidney. He was treated with surgical intervention and had resolution of his hydronephrosis and his flank and groin pain. He also had improvement of his back pain. Conclusions: This report shows an unusual cause of hydronephrosis-a pseudomeningocele presenting as an abdominal mass that compressed the ureter.