title: Branchial sinus of the piriform fossa: reappraisal of third and fourth branchial anomalies.
abstract: OBJECTIVE
  The objective of this study was to review clinical and embryologic aspects of third and fourth branchial anomalies.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  We reviewed the institutional and departmental databases at our institution to identify all cases of third and fourth branchial anomalies encountered from 1992 to 2006. All patient records were examined with respect to demographics, clinical history, and radiologic and pathologic reports.
  
  
  RESULTS
  We identified 17 cases of third and fourth branchial anomalies, the largest series of its kind reported to date. The lesions were predominantly left sided, all presenting with neck infection. Fistula formation was iatrogenic, secondary to incision and drainage. Preoperative direct laryngoscopy always revealed a pit within the apex of the piriform fossa. Surgical excision involved ipsilateral thyroidectomy as the lesion passed through the thyroid gland. No lesions following the classical course of a either a third or fourth branchial anomaly were identified.
  
  
  CONCLUSIONS
  The clinical presentation of branchial sinuses arising from the piriform fossa is more in keeping with derivation from the thymopharyngeal duct (of the third pouch) than the hypothetical course of third and fourth branchial fistulae.
authors: Department of Otolaryngology, The Hospital for Sick Children, Toronto, Ontario, Canada. adr.james@utoronto.ca
authors: Adrian
authors: A
authors: James
authors: Craig
authors: C
authors: Stewart
authors: Paul
authors: P
authors: Warrick
authors: Constance
authors: C
authors: Tzifa
authors: Vito
authors: V
authors: Forte
mesh_terms: D000293:Adolescent; D001934:Branchial Region / Q000002:abnormalities* / Q000000981:diagnostic imaging / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed