Ectopic anus with barrel gun perineum rare type of anorectal anomaly.

Perineal ectopic anus in female infants is not a very uncommon congenital anorectal anomaly with opening into the low vaginal or vulvar region. However, ectopic anus with barrel gun perineum is a less common variety. Patients generally present with frequent history of constipation, but may seek medical help for just aesthetic reasons. We present here one such case of an asymptomatic seven years old female with the rare form of anterior ectopic anus with barrel gun perineum without any fistulous communications with an innovative method of demonstration of the anomaly by using ultrasound gel as rectal contrast in MRI pelvis.