Isolated First Branchial Cleft Anomalies of the External Auditory Canal.

BACKGROUND Branchial cleft anomalies are congenital aberrations of the first to fourth pharyngeal pouches. First branchial cleft anomalies are classified into 2 subtypes according to anatomical and histological features. Their diagnosis can be difficult and depends on radiological and histological findings. In contrast, the required treatment is surgical removal, owing to the high risk of infection or malignancy. This case report introduces a first branchial cleft anomaly in an older woman with exclusive involvement of the external auditory canal (EAC). CASE REPORT This case report introduces a first branchial cleft anomaly in an 82-year-old woman with exclusive involvement of the EAC. She reported a history of mixed moderate hypoacusis and recurrent otitis media in the last year, without facial nerve involvement. Computed tomography and magnetic resonance imaging were performed to plan surgical treatment, which consisted of canaloplasty and Thiersch grafting. The histopathological examination on operative findings revealed a cystic lesion that was lined by cylindrical epithelium adjacent to the squamous cells, compatible with a diagnosis of first branchial arch malformative residues. CONCLUSIONS This is the unique case of first branchial cleft anomalies reported in an adult patient that exclusively involved the EAC. The onset of the disease was atypical, and surgery with the total removal of the lesion was the only possible treatment. Histopathology results revealed cylindric epithelium not represented in the EAC, compatible with first branchial arch malformative residues. This rare condition is a potential diagnostic option that should be considered in the differential diagnosis of cysts of the EAC.