They represent ectodermal inclusions, which are related to embryonic remains that form the ear. They are present at birth. They are most frequently located on the right side, are usually short in length, end in a blind fundus, and do not connect internally with the external auditory canal*.
Treatment is controversial as they may remain asymptomatic, but excision is generally recommended when they present a palpable cyst or discharge of material from the sinus tract*, from one year of age.