Retrorectal tailgut cyst.

Retrorectal tailgut cysts are rare congenital cystic lesions that are found in the presacral space. A case of a woman in her 50s who had an incidental finding of a 7 cm presacral mass after an initial chief concern of flank pain is presented in this report. Further work-up with MRI and colonoscopy demonstrated an extraluminal cystic mass within the retrorectal space with hyperintense foci on T1-weighted imaging. A posterior approach was used to access the retrorectal space and remove the cystic mass. Pathology demonstrated findings consistent with a tailgut cyst, and the patient made a full recovery following the procedure.