The canal of Nuck in females is formed of an invagination of parietal peritoneum that goes with the round ligament through the inguinal canal. Complete obliteration takes place during 1st year of life and its persistence result into hydrocele (female hydrocele) or hernia. Although it was thought to be extremely rare, nowadays it is diagnosed more frequently as physicians and radiologists became more familiar with this developmental disorder.The current report presents a case of a 14-year-old girl complaining of slowly growing non painful swelling at the left inguinal region with no history of previous intervention. Post contrast multislice CT examination of the pelvis and inguinal region was requested aiming to define the extent and nature of the lesion. Multiplanar 2D and 3D images showed cystic lesion at the left inguinal canal having an intra pelvic component and midway constriction at the level of the internal inguinal ring providing accurate data for successful surgical planning.