Peripheral calcifying odontogenic cyst: A case report and literature review

Abstract

Calcifying odontogenic cyst (COC), also known as Gorlin cyst, is a type of developmental odontogenic cyst characterized histologically according to the latest (2022) WHO classification by frequently calcifying ghost cells in epithelium. A COC is usually intraosseous but occasionally arises in soft tissue; these are called peripheral COCs (PCOCs). We describe a PCOC that manifested as a progressive growth of a gingival mass in the maxilla of a 10-year-old Japanese boy. Radiological examinations revealed no remarkable findings. An excisional biopsy was thus conducted for a definite diagnosis. The histological examination confirmed the diagnosis of PCOC with the presence of characteristic ghost cells and sporadic calcifications; no surrounding bone tissue was present. No recurrence or complication were noted at the 1-year follow-up. We also extracted 39 cases from the literature that meet the current WHO criteria and statistically analyzed the 40 cases including our patient's. A multivariate analysis showed that the gender and location (maxilla or mandible) are two major factors related to the age factor, indicating that PCOC is more common in the maxilla of younger males. Additionally, the PCOCs were smaller than the COCs and had a significantly lower calcification rate on radiography (p < 0.001), probably because PCOCs are usually resected when the lesion is small. Even if ghost cell calcification is present, it may not be large enough to be radiologically visible.