Iatrogenic spinopelvic cerebro-spinal fluid fistula. Case report.

Perineurial cysts usually affect the lumbosacral spinal nerve roots, but sometimes they can erode the sacrum and reach the retroperitoneal space. In such cases misdiagnosis can lead to an improper treatment and cause serious complications. A presacral mass was diagnosed in a young woman during routine ultrasound investigation, and an exploratory laparotomy was performed. A large, fluid-containing cyst was found and marsupialized into the pelvis. After operation the patient experienced headache, vomiting and VI cranial nerve palsy whenever she stood up. By radiculography a iatrogenic spinopelvic cerebro-spinal fluid fistula was diagnosed, which required further surgery to be repaired. The presence of a giant perineurial cyst in the pelvis in unusual but must be considered in the differential diagnosis of presacral masses; the exceptionally rare case reported in this paper is exemplar of the harmful complications that an incautious procedure can determine.