Dentigerous cyst

Case contributed by Assoc Prof Craig Hacking


Right jaw swelling.

Patient Data

Age: 45 years
Gender: Male

A 4 cm well-defined thin-walled cyst in the right hemimandible is associated with the crown of an unerupted molar tooth (48).


There is 50 mm AP-oblique x 14 mm transverse-oblique x 40 mm craniocaudal unilocular cyst in the body of the right hemi-mandible with minimal extension into the anterior aspect of the ramus. The lesion is of intermediate attenuation value with an average density of 34HU. There is thinning and expansion of the lingual and inferior cortices of the body of the right hemi-mandible. There is mesially rotated un-erupted right lower third molar tooth (48) with the cyst surrounding the crown of the tooth. There is pressure erosion and truncation of the apex of the lateral root of 46 and the mesial and lateral roots of 47. The inferior alveolar nerve canal is displaced laterally by the cyst and the un-erupted tooth. There is focal dehiscence of the canal anteriorly close to level of the mental foramen.

No cortical breach or pathological fracture. No extra osseous soft tissue extension of the lesion.

Case Discussion

Unilocular cyst in the body of right hemi-mandible associated with the crown of an un-erupted molar tooth. The imaging appearances are probably of dentigerous cyst or keratocystic odontogenic tumor. A unilocular ameloblastoma should be also considered.

The lesion was enucleated and histology confirmed a dentigerous cyst.

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Case information

rID: 37830
Published: 24th Jun 2015
Last edited: 24th Apr 2021
System: Head & Neck
Inclusion in quiz mode: Included

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