This site is targeted at medical and radiology professionals, contains user contributed content, and material that may be confusing to a lay audience. Use of this site implies acceptance of our Terms of Use.

Dentigerous cyst

Dentigerous cysts (also called follicular cysts) are benign, non-inflammatory odontogenic cysts that are thought to be developmental in origin.

Epidemiology

Dentigerous cysts are the second most common odontogenic cysts after those related to the roots of the teeth (periapical cysts) 3. They usually present in the 2nd to 4th decades of life and are rarely seen in childhood because they almost exclusively occur in secondary dentition 1-3

Pathology

A dentigerous cyst is formed by the hydrostatic force exerted by the accumulation of fluid between reduced enamel epithelium and the tooth crown of unerupted teeth 1-3,5. As such the cyst encloses the crown and is attached at the neck at the cemento-enamel junction 5. They almost exclusively occur in permanent dentition.  The cyst is lined by stratified squamous nonkeratinizing epithelium.

Over 75% of all cases are located in the mandible, with the most commonly involved teeth being 1,3:

  • mandibular third molar (most common)
  • maxillary third molar (2nd most common)
  • maxillary canine
  • mandibular second premolar
Associations

Dentigerous cysts are usually solitary, however multiple cysts are recognised to occur in association with syndromes such as 

Clinical presentation

Typically, dentigerous cysts are painless and discovered during routine radiographic examination, however they may be large and result in a palpable mass. Additionally as they grow they displace adjacent teeth 2.

Several cases of dentigerous cysts presenting as recurrent head and neck infection or as a deep neck space abscess have been described.

Radiographic features

Dentigerous cysts are frequently seen on OPGs, and often require no further imaging to make the diagnosis. CT and MRI give additional information, and help in distinguishing this entity from other cystic lesions of the mandible and maxilla. 

When small, it is difficult to differentiate a dentigerous cyst from a large but normal dental follicle. A working definition is that a dentigerous cyst exists when the distance between the crown and dental sac is greater than 2.5 - 3.0mm 5-6.

Plain film (OPG)

Radiographically, dentigerous cysts appear as unilocular well defined pericoronal radiolucencies centred on an impacted or unerupted tooth. They have a thin regular sclerotic margin and expand the overlying cortex without cortical breach (unless superimposed fracture or infection). Their size is extremely variable, ranging from only slightly greater in size than a normal follicle to very large, appearing to hollow-out the majority of the jaw 1-4

Erosion / resorption of the roots of adjacent teeth is not sometimes seen 6.

CT

CT appearances mirror those of plain film. The relationship to the unerupted tooth can often be better appreciated, and the cyst cavity is filled with water density fluid. Maxillary lesions may project superiorly into the paranasal sinuses or nasal cavity 3-4.

MRI

The main role of MRI is help distinguish these lesions from other cystic lesions of the jaw, when appearances are atypical.

  • T1 - low signal, similar to water /  CSF
  • T2 - high signal, similar to water / CSF
  • T1 C+ (Gd) - no solid component or enhancement, except for potentially a thin peripheral rim of enhancement 1,3.

Complications

  • pathological jaw fracture - if large enough
  • very rarely dentigerous cysts may develop into a mural ameloblastoma 2.
  • there is a potential of development of squamous cell carcinoma in the context of chronic infection

Treatment and prognosis

Treatment usually involves removal of the entire cyst and the associated unerupted tooth. In patients with very large lesion or who are unfit medically, marsupialisaiton is an option 6

Recurrence is uncommon, but may occur if parts of the cyst lining are left in situ 6.

Differential diagnosis

When small, it is difficult to differentiate a dentigerous cyst from a large but normal dental follicle 5-6.

When larger, the differential is essential that of lytic lesions of the jaw and includes:


Related articles

Lucent lesions of the jaw

General reading

Pathology

Updating… Please wait.
Loadinganimation

 Details successfully updated.

Error Unable to process the form. Check for errors and try again.

 Thank you for updating your details.