Calcifying Cystic Odontogenic Tumor

Synonym / Acronym

Calcifying odontogenic cyst, calcifying epithelial odontogenic cyst, Gorlin cyst.

Definition

Calcifying cystic odontogenic tumor is a rare developmental odontogenic lesion that occupies a position between a cyst and benign tumor as it has characteristics of a solid neoplasm (epithelial proliferation and continuous growth into large ghost cells) and some features of a cyst. Formerly known as calcifying odontogenic cyst, it is now classified as a benign tumor by WHO. It should not be confused with calcifying epithelial odontogenic tumor (Pindborg tumor).

Clinical Features

Calcifying cystic odontogenic tumor can occur at any age with two peaks: from 10-19 and at 70 years of age. The lesion is slowly growing and asymptomatic. Occasionally, it can cause pain, root resorption and displacement of teeth. Sometimes the lesion destroys the cortical plate and gives appearance of a mass involving the gingivae. The patient may report a discharge when the lesion becomes advanced.

Radiographic Features

Initially, the lesion appears well-defined and well-corticated borders but can vary to ill-defined and irregular. It can be unilocular or in rare cases multilocular. It can appear completely radiolucent or with scattered calcifications when the lesion matures giving it a “salt and pepper” appearance. The opacities can range from small flecks to large masses.

Differential Diagnosis

In cases where the lesion is without calcifications and located pericoronal to unerupted tooth; it can resemble a dentigerous cyst. KCOT and ameloblastoma can be included in the differential diagnosis. If calcifications are present we can include adenomatoid odontogenic tumor, ameloblastic fibro-odontoma, calcifying epithelial odontogenic tumor. However, the classic place for calcifying epithelial odontogenic tumor is not in favor of ameloblastic fibro-odontoma or CEOT.

Treatment

Although this lesion can exhibit continuous growth due of its neoplastic characteristics, simple enucleation and curettage is the treatment of choice. Periodic radiographic evaluation is recommended with more solid neoplastic variants.

Case Reports

HISTORY: A 23-year-old female was referred for a Cone Beam CT scan for evaluation of a lesion in the left mandible.


FINDINGS: There is a well-defined partially corticated mixed lesion in the left mandible. The lesion is mainly radiolucent but there are radiopaque masses that represent calcifications in the posterior part of the lesion. The lesion extends from the apex of tooth #20 to #17. It extends from the alveolar crest superiorly to the inferior cortex inferiorly. The lesion has caused a bucco-lingual expansion as seen on the axial slices and cross-sectional images. The expansion is more lingually. There is thinning of the cortical borders. There is extensive roots resorption. Tooth #17 appears to be displaced posteriorly and superiorly. It appears that the mandibular canal has been displaced superiorly and lingually. Calcifications can be seen clearly on cross-sections 16-18.


IMPRESSION: Given the radiographic findings calcified calcifying cystic odontogenic tumor is on the first of the differential list. Ameloblastoma can cause extensive expansion, thinning and resorption of teeth but it can be completely radiolucent or with coarse septa but does not produce calcifications. COF can have mixed radiographic appearance with extensive expansion and resorption of teeth but rarely causes root resorption.