title: Thymopharyngeal duct cyst: an unusual variant of cervical thymic anomalies.
abstract: BACKGROUND
  The thymus develops from the third pharyngeal pouch and descends from the neck into the anterior-superior mediastinum. Thus, it is possible to have thymic remnants in the neck, which most often present as a cervical mass during childhood. One type of cystic thymic remnant is the thymopharyngeal duct cyst, a remnant of one of the paired tracts of embryological thymic descent. Thymopharyngeal duct cysts are rare lesions that can have a similar presentation to more commonly encountered childhood neck masses.
  
  
  OBJECTIVE
  To review the embryological development of cervical thymic remnants and to report our experience with the thymopharyngeal duct cyst.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Tertiary care center.
  
  
  METHODS
  Two children who presented with asymptomatic neck masses that were caused by cystic remnants of the thymopharyngeal duct.
  
  
  RESULTS
  Both patients underwent preoperative computed tomography, which revealed a multiloculated mass coursing adjacent to the carotid sheath. Surgical treatment was the definitive therapy for both patients, although neither patient had a definitive preoperative diagnosis. In both cases, the mass was approached through an incision anterior to the sternocleidomastoid muscle, and dissection proceeded along the length of the carotid sheath. A fibrous cord extending into the mediastinum was found in both patients. There were no postoperative complications. Histopathologic evaluation revealed the presence of mature thymic elements within the wall of a multiloculated cyst.
  
  
  CONCLUSIONS
  Thymopharyngeal duct cysts must be considered in the differential diagnosis of pediatric neck masses. Computed tomography is helpful to delineate the relationship to the carotid sheath. Complete surgical excision is the appropriate therapy in a majority of cases, with minimal morbidity when careful attention is paid to vital structures.
authors.affiliation: Department of Otolaryngology, The Mount Sinai Medical Center, One Gustave L. Levy Place, Box 1189, New York, NY 10029, USA. kaufmanmatthew@hotmail.com
authors.forename: M R
authors.initials: MR
authors.lastname: Kaufman
authors.forename: S
authors.initials: S
authors.lastname: Smith
authors.forename: M A
authors.initials: MA
authors.lastname: Rothschild
authors.forename: P
authors.initials: P
authors.lastname: Som
mesh_terms: D002648:Child; D003560:Cysts / Q000000981:diagnostic imaging* / Q000196:embryology / Q000601:surgery; D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D010608:Pharyngeal Diseases / Q000000981:diagnostic imaging* / Q000601:surgery; D013950:Thymus Gland / Q000196:embryology; D014057:Tomography, X-Ray Computed