Anomalies of the first branchial cleft.

Eleven cases of first branchial cleft duplication anomalies are classified into types I and II. Type I defects are associated with the first cleft and are duplication anomalies of the membranous external auditory canal. Type II defects are associated with the first cleft and first and second arches, and, as such, are associated with defects of the membranous external auditory canal and cartilaginous elements. Microscopical examination of tissue in type I anomalies shows a cyst lined by skin without adnexal structures and without cartilage. Type II anomalies usually contain all elements. Misdiagnosis, infection, and recurrences are common with these lesions. Clinically, they may drain through the neck and external auditory canal. Surgical excision must be complete or there will be recurrence. The facial nerve must be identified and protected during the excision.