title: Fourth branchial arch anomaly and pyriform sinus fistula as a rare cause of recurrent retropharyngeal abscess and thyroiditis in an adult.
authors.forename: Levent
authors.initials: L
authors.lastname: Erisen
authors.forename: Hakan
authors.initials: H
authors.lastname: Coskun
authors.forename: Mufit
authors.initials: M
authors.lastname: Parlak
authors.forename: Adnan
authors.initials: A
authors.lastname: Ozmen
mesh_terms: D000328:Adult; D001934:Branchial Region / Q000002:abnormalities*; D005260:Female; D006801:Humans; D009302:Nasopharyngeal Diseases / Q000150:complications* / Q000151:congenital; D012008:Recurrence; D016156:Respiratory Tract Fistula / Q000150:complications* / Q000151:congenital; D017703:Retropharyngeal Abscess / Q000209:etiology*; D013966:Thyroiditis / Q000209:etiology*