Radiological findings of tailgut cyst in a fetus.

Tailgut cyst, or retrorectal cystic hamartoma, is a rare congenital lesion found in the presacral space. The lesion has not been adequately reported in the literature. In this article, we describe a case of tailgut cyst that was demonstrated as a large cystic lesion within a fetal pelvis using ultrasonography and magnetic resonance imaging.