Prenatal Diagnosis of a Cyst of the Canal of Nuck Associated With an Ovarian Cyst and Acute Polyhydramnios

In the female, the canal of Nuck is a tubular fold of parietal peritoneum that travels along with the round ligament through the inguinal canal to its attachment on the labia majora. The canal of Nuck is analogous to the processus vaginalis in the male. In embryonic development, this pathway typically obliterates early in life; however, in some cases, it may partially or completely fail to close. This failure to obliterate can lead to complications ranging from a cyst of the canal of Nuck (also known as a female hydrocele) to herniation and incarceration of abdominal and pelvic organs. There is little information available in the medical literature concerning this rare condition; therefore, it is important for sonographers, physicians, and surgeons to be familiar with this developmental abnormality. This report represents the first prenatal case of a cyst of the canal of Nuck, along with the unique combination of a large left fetal ovarian cyst and acute polyhydramnios. The embryology, incidence, differential diagnosis, management, and treatment of these female conditions are discussed.