Dentigerous cyst

From Dog
A dentigerous cyst in a 2-year-old Shih Tzu with a large dentigerous cyst associated with an unerupted left maxillary canine[1]

Dentigerous cysts are an infrequently occurring cancer-like lesion arising from the cellular components of the developing dental follicle. It is often associated with the crown of an unerupted permanent tooth[2].

Dentigerous cysts arise from the epithelial remnants of the enamel organ or the reduced enamel epithelium that surrounds the crown during odontogenesis[3]. They subsequently enclose the crown of the unerupted tooth and are attached to the tooth at the cemento-enamel junction.

Dentigerous cysts are usually a developmental problem due to a physical barrier (impacted tooth) or a lack of eruptive forces (embedded tooth)[4]. Rare iatrogenic cases have been reported following the extraction of a deciduous tooth[5].

Although one tooth is commonly affected, often the mandibular first premolar or canine[6], this can be a bilateral disease, with brachycephalic dogs more frequently affected[7].

Dentigerous cysts can be diagnosed at any age, and most dogs are accidentally diagnosed or present with facial symmetry or an oral mass. Dentigerous cysts can greatly weaken the surrounding bone or invade the nasal cavities, resulting in secondary infections[8] and pathological fractures[9].

Diagnosis is usually based on clinical examination, but histological analysis is usually required to eliminate other differential causes. Radiography usually show a circular radiolucent lesion with a well-defined cortex that is uniform, thin and has a radio-opaque line[10].

A differential diagnosis would include squamous cell carcinoma, osteochondroma, ameloblastoma, melanoma, dental abscess or bone cyst.

Removal of the unerupted tooth and enucleation of the entire cyst wall is curative in most cases[11].

References

  1. D'Astous J (2011) An overview of dentigerous cysts in dogs and cats. Can Vet J 52(8):905-907
  2. Lobprise HB & Wiggs RB (1992) Dentigerous cyst in a dog. J Vet Dent 9(1):13-15
  3. Regezi JA et al (2008) Oral Pathology: Clinical Pathologic Correlations. 5th ed. xiv. St Louis, Missouri: Saunders Elsevier. p:418
  4. Hoffman S (2008) Abnormal tooth eruption in a cat. J Vet Dent 25:118–122
  5. Manfra Marretta S et al (1989) An iatrogenic dentigerous cyst in a dog. J Vet Dent 6:11
  6. Verstraete FJ et al (2011) Clinical signs and histologic findings in dogs with odontogenic cysts: 41 cases (1995-2010). J Am Vet Med Assoc 239(11):1470-1476
  7. Okuda A et al (2007) Review of 117 impacted (98 permanent and 19 deciduous) teeth in 46 dogs. Proceedings, 21st Ann Vet Dental Forum pp:375–377
  8. Fulton A & Fiani N (2011) Diagnostic imaging in veterinary dental practice. Dentigerous cyst with secondary infection. J Am Vet Med Assoc 238(4):435-437
  9. Lemmons MS et al (2006) Diagnostic imaging in veterinary dental practice. Unerupted tooth resulting in a dentigerous cyst causing resorption of bone. J Am Vet Med Assoc 228:1023–1024
  10. DuPont GA & DeBowes LJ (2009) Atlas of dental radiography in dogs and cats. 1st ed. xi. St Louis, Missouri: Saunders Elsevier. p:268
  11. Watanabe K et al (2004) Odontogenic cysts in three dogs: one odontogenic keratocyst and two dentigerous cysts. J Vet Med Sci 66(9):1167-1170