dentigerous cyst

Definition: Dentigerous cysts are developmental odontogenic cysts. They arise in association with impacted teeth. Their origin is from the reduced enamel epithelium between the follicle and the tooth crown.

Dentigerous cysts are developmental odontogenic jaw cysts, commonly manifesting in the second and third decades of life.

Dentigerous cyst is usually associated with impacted teeth (third molars, maxillary canines). It has stratified squamous epithelium and may or may not be inflamed. It is the second most common odontogenic and jaw cyst, behind periapical cysts.

Images

 radiology

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 microscopy

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 Rushton bodies in dentigerous cyst

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Dentigerous cysts are benign odontogenic cysts that are associated with the crowns of permanent teeth.

They are usually single in occurrence and located in the mandible. Multiple cysts are reported in patients with conditions such as mucopolysaccharidosis and basal cell nevus syndrome.

A dentigerous cyst surrounds the crown of a tooth that has not migrated into the oral cavity, but still lies buried in the jaw bone. This cyst arises through fluid accumulation between tooth crown and collapsed enamel organ.
Dentigerous cysts most commonly involved the third molars, but any unerupted tooth may be affected. They account for 25% of all jaw cysts.

Dentigerous cysts are usually asymptomatic, but maybe associated with pain, swelling and may grow so large to displace teeth or erode bone.

Importantly, to the oral surgeon, clinical differentiation is frequently not possible between dentigerous cyst, odontogenic keratocyst, and unicystic ameloblastoma.

Macroscopy

Grossly and radiologically, the cyst appears as a bag in which the crown part of the embedded tooth, mostly the mandibular third molar or the maxillary canine, protrudes and forms a collar at the neck of the tooth at the border between root and crown.

Microscopy

The cyst wall has a thin epithelial lining that ususally consists of only two to three layers of cuboidal cells. Also, mucus-producing cells as well as ciliated cells may be observed.

The fibrous cyst wall may contain varying amounts of odontogenic epithelial islands.

In case of inflammation, the epithelium becomes hyperplastic and resembles the lining of a radicular cyst. In those cases, radiological features are decisive.

A radicular cyst is a radiolucent lesion at the root tip of a decayed tooth; the dentigerous cyst is a radiolucent lesion surrounding the crown part of an embedded tooth.

The cyst enlarges by accumulation of fluid between the proliferating reduced enamel epithelium and the crown.

Possible Rushton bodies

Radiology

The radiographic features of dentigerous cysts are those of lesions with well circumscribed, corticated borders. They are usually unilocular. The radiographs are not diagnostic and differentiation from odontogenic keratocyst and unicystic ameloblastoma is not possible using this modality either.

Microscopy

Microscopically, dentigerous cysts have a non-keratinized stratified squamous epithelial lining which may have occasional sebaceous or mucus cell metaplasia.

There is often a thick fibrous connective tissue wall. Inflammation can be minimal or marked.

Differential diagnosis

 periapical (radicular) cyst.

• These cysts are inflammatory and not developmental.
• They arise when epithelium around the root is stimulated by inflammation.
• The histopathologic features may be identical to dentigerous cysts, therefore the radiographic or clinical description of the cyst is required.

Evolution

Very rarely, dentigerous cysts may develop an ameloblastoma or develop dysplastic epithelium and evolve into squamous carcinoma.

Treatment

The treatment of dentigerous cyst is curettage and removal of the unerupted tooth.

Predisposition

 mucopolysaccharidoses
 basal cell nevus syndrome (Gorlin syndrome)

Credits

 USCAP 2005

See also

 cysts of the jaws
 odontogenic cysts
 developmental cysts
 inflammatory cysts

References

 Inverted impaction of a mandibular premolar associated with a dentigerous cyst: report of a case. Bhatia SK, Collard M, Divcic D, Hunter L. Dent Update. 2009 Jul-Aug;36(6):374-6. PMID: 19743667