Calcifying Odontogenic Cyst

The calcifying odontogenic cyst (COC) refers to an odontogenic benign lesion, and it was first proposed by Gorlin in 1962 as an independent jaw cyst [1–6]. Its incidence rate accounts for less than 2% of total odontogenic cysts and tumors, and there is still controversy about their tissue origin: reduced enamel epithelium, residual dental plate epithelium and others. In the previous WHO classification, it was named a “calcifying cystic odontogenic tumor.” In the new classification of head and neck solid tumors in 2017, WHO recovered its name to the calcifying odontogenic cyst. The patient’s age peak ranges from 10 to 19 and there is no obvious gender difference. The predilection site is the maxillary premolar area, mostly observed in bone. Sometimes, it was found in the extraosseous soft tissue and was mainly seen in the soft tissue of the dental region. The most common clinical symptom is progressive, painless and facial asymmetric swelling, and it may be manifested as tongue protrusion, tooth displacement, tooth root absorption and cortical bone resorption. In the imaging, it is manifested as the single chamber radiolucent shadow with clear boundaries and sometimes shows the multilocular manifestation. There are some reports of cases where the cyst wall surrounds the neck of impacted canines and molars. Typical histologic findings: Epithelial structures similar to ameloblastoma and epithelial lining composed of shadow cells (calcified tendency) [7–11]. It may be accompanied by other odontogenic tumors, such as ameloblastoma, ameloblastoma Fibroma, odontogenic adenoid tumor, and odontogenic keratocyst. The most common one is odontoma. Most lesions are cystic changes, some cases present as solid lesions, and a few cases have a tendency toward malignancy. At present, there is no specific treatment guidance on COC. The cyst removal combined with scaling is the top priority for treatment. There was less postoperative recurrence, and there was no recurrence report for the peripheral type [12–18].