The inguinal canal is traversed by the spermatic cord in men and the round ligament of uterus in women. The round ligament is attached to the uterine cornu near the origin of fallopian tube at one end and to the ipsilateral labia majora at the other. The round ligament accompanies a pouch of parietal peritoneum in the inguinal canal, which is known as 'canal of nuck'. It is analogous to the processus vaginalis in males. Incomplete obliteration of the peritoneal pouch causes indirect inguinal hernia or hydrocele of the canal of nuck; a very rare condition in women. As these types of cases are rarely seen in surgical practice we present a case of such little-known developmental disorder in a three-year-old girl. She presented with irreducible, tender right inguino-labial swelling with tachycardia simulating incarcerated inguinal hernia, which necessitates emergency surgical exploration. On exploration it was found to be an encysted hydrocele of canal of nuck; so although rare, this entity should be considered in differential diagnosis in a female child presented with inguino-labial swelling.
Keywords: Encysted hydrocele; Processus vaginalis; Round ligament.