Prenatally detected congenital perineal mass using 3D ultrasound which was diagnosed as lipoblastoma combined with anorectal malformation: case report.

We report a case of prenatally diagnosed congenital perineal mass which was combined with anorectal malformation. The mass was successfully treated with posterior sagittal anorectoplasty postnatally. On ultrasound examination at a gestational age of 23 weeks the fetal perineal mass were found on the right side. Any other defects were not visible on ultrasonography during whole gestation. Amniocentesis was performed to evaluate the fetal karyotyping and acetylcholinesterase which were also normal. As the fetus grew up, the mass size was slowly increased more and more. At birth, a female neonate had a perineal mass on the right side as expected. During operation, the anal sphincteric displacement was found near the mass and reconstructed through posterior sagittal incision. This is the first reported case of prenatally diagnosed congenital perineal mass, after birth which was diagnosed as lipoblastoma and even combined with anorectal malformation. This case shows that it can be of clinical importance to be aware of this rare fetal perineal mass in prenatal diagnosis and counseling.