Final Diagnosis -- A 45 year old man with foregut duplicaiton cyst of the tongue

DIAGNOSIS:    FOREGUT DUPLICATION CYST OF THE TONGUE

DISCUSSION:

The foregut gives rise to the pharynx and its associated structures as well as to the lower respiratory tract, esophagus, stomach, duodenum, and hepatobiliary tract1. Heterotopic rests of foregut- derived epithelium may be encountered as a foregut duplication cyst, also known as foregut cyst/ enteric duplication cyst/ gastrointestinal cyst/ choristomatic cyst. The epithelium in these duplication cysts may be gastric, respiratory, intestinal, colonic, or pancreatic and may not necessarily correlate with the level at which the cyst is found. Mixed mucosal lesions are common. 2 Bronchogenic cysts belong to the same category but are differentiated by the presence of hyaline cartilage.

Foregut duplication cysts of the head and neck are extremely rare, with only 65 cases reported as of 1997. 3 They are three times more common in males and usually occur in infancy, but have manifested in adults as an asymptomatic swelling 3. When large these cysts may cause respiratory distress, difficulty with oral feedings, increased salivation, and speech disturbances.4 An exceptional case of adenocarcinoma arising in a foregut duplication cyst of the tongue has been reported. 5

Diagnostic features of a foregut duplication cyst include 1) a coat of alimentary muscle, usually smooth muscle, 2) attachment to the alimentary tract, 3) a foregut derived mucosal lining. Choristomatic and heterotopic cysts are not required by definition to have a coat of muscle.6 The cyst may be entirely enclosed within the body of the tongue, floor of mouth, hypopharynx, anterior neck, larynx, or submandibular gland, and it may communicate with the surface.3

The embryology of this lesion in the tongue is unclear but several theories have been postulated:

  1. When the embryo is at the 3 to 4mm stage (4 weeks), the undifferentiated primitive stomach lies in the mid neck close to the primordium of the tongue. The endodermal gastric mucosa may become entrapped in the midline of the tongue by fusion of the lateral lingual swellings over the tuberculum impar.7 This however does not explain the presence of these lesions in the lateral tongue and presence of colonic / intestinal mucosa.
  2. Daley et al 8 proposed that undifferentiated endodermal cells that normally cover the floor of the primitive stomadeum become entrapped and are subjected to a different embryonic induction. This results in gastrointestinal differentiation.
  3. Veeneklaas 9 initially proposed the currently accepted explanation in 1952, when he observed vertebral clefts and rib anomalies in association with intestinal duplications. He suggested that a disturbance in the development of the notochord and surrounding structures accounted for misplaced segments of gastrointestinal mucosa and the adherent endodermal cells became entrapped during the infolding of the notochordal plate.
  4. These lesions may arise from thyroglossal duct cyst or salivary retention cysts7, 10. However the lesions that occur in the anterior tongue are too anterior to arise from thyroglossal cyst, and, moreover, thyroid follicles have never been associated with heterotopic gastric mucosa 8 and salivary gland tissue must first dedifferentiate and then differentiate into gastrointestinal tissue.

Clinically, the differential diagnosis include teratomas, dermoid cyst, thyroglossal duct cyst, lingual thyroid, lymphangioma, hemangioma, hamartomas, gliomas, retention cyst, squamous cell carcinoma, rhabdomyosarcoma, and granular cell tumor.4 Magnetic resonance imaging is the investigation of choice though preoperative diagnosis is rarely made. Complete excision of cyst with removal of the mucosal lining is the treatment of choice. Aspiration alone results in recurrence, and the functional mucosa will continue to secrete mucus and acid if left intact with a risk of ulceration and bleeding. The long-term prognosis is excellent 2 with only one case reported with adenocarcinoma arising in the cyst 5.

REFERENCE:

  1. Moore KLP, Persaud TVN. The Developing Human: Clinically Oriented Embryology. 7th ed: Philadelphia, Pa: WB Saunders Co; 2003.
  2. Eaton D, Billings K, Timmons C, Booth T, Biavati JM. Congenital foregut duplication cysts of the anterior tongue. Arch Otolaryngol Head Neck Surg. 2001;127:1484-7.
  3. Ohbayashi Y, Miyake M, Nagahata S. Gastrointestinal cyst of the tongue: a possible duplication cyst of foregut origin. J Oral Maxillofac Surg. 1997;55:626-8; discussion 629-30.
  4. Lalwani AK, Lalwani RB, Bartlett PC. Heterotopic gastric mucosal cyst of the tongue. Otolaryngol Head Neck Surg. 1993;108:204-5.
  5. Volchok J, Jaffer A, Cooper T, Al-Sabbagh A, Cavalli G. Adenocarcinoma arising in a lingual foregut duplication cyst. Arch Otolaryngol Head Neck Surg. 2007;133:717-9.
  6. Mirchandani R, Sciubba J, Gloster ES. Congenital oral cyst with heterotopic gastrointestinal and respiratory mucosa. Arch Pathol Lab Med. 1989;113:1301-2.
  7. Woolgar JA, Smith AJ. Heterotopic gastrointestinal cyst of oral cavity: a developmental lesion? Oral Surg Oral Med Oral Pathol. 1988;66:223-5.
  8. Daley TD, Wysocki GP, Lovas GL, Smout MS. Heterotopic gastric cyst of the oral cavity. Head Neck Surg. 1984;7:168-71.
  9. Veeneklaas GM. Pathogenesis of intrathoracic gastrogenic cysts. AMA Am J Dis Child. 1952;83:500-7.
  10. Gruskin P, Landolfe FR. Heterotopic gastric mucosa of the tongue 94 vol;

Contributed by Nidhi Aggarwal, MD and E. Leon Barnes, Jr., MD.



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