Branchial cleft anomalies: hybrid “Branchial Inclusion” theory

Purpose Branchial cleft anomalies (BCAs) are developmental malformations of the head and neck region. Their histogenesis has been the subject of controversy and is not fully understood. This study aimed to test all present developmental theories (“branchial apparatus,” “precervical sinus,” “thymopharyngeal,” and “inclusion” theories) on a sample of 48 BCAs from a single institution. Methods We performed a retrospective analysis of clinical–epidemiological and anatomical–pathological characteristics of BCAs treated over a 12-year period in our hospital. Results Overall, 46 patients (24 [52.17%] women and 22 men [47.83%]) underwent surgical excision of 48 BCAs. The mean patient age at presentation was 31.65 ± 19.40 years. Branchial cleft cysts were found in 42 (87.50%) cases, and branchial cleft sinuses were found in six (12.50%) cases. Eight (16.67%) BCAs were distributed in the preauricular region, 34 (70.83%) at the anterior border of the sternocleidomastoid muscle (SCM), three (6.25%) at the posterior border of the SCM, two (4.17%) in the suprasternal notch, and one (2.08%) in the retrosternal space. Histopathologically, 39 (81.25%) BCAs had a lymphoepithelial structure and nine (18.75%) BCAs had solitary epithelial cells. Inflammation and infection were observed in 24 (50%) and 12 (25%) cases, respectively. Conclusion None of the hypothesized developmental theories fully explain the embryonic origin of BCA in our study sample. A possible explanation of BCA histogenesis is through the hybrid “branchial inclusion” theory.