Pericoronal radiolucency associated with incomplete crown
A 12-year-old female patient was referred from a private dental clinic for evaluation of a cystic lesion in the left mandibular posterior region. On clinical examination, there was a swelling of the left mandible that was hard to the touch, but the pain and soft tissue swelling, which was the initial chief complaint of the patient, had subsided after the administration of antibiotics for several weeks. A panoramic radiograph revealed a well-defined round unilocular radiolucency surrounding the developing crown of the left lower third molar which had not developed to the cementoenamel junction yet (). The CBCT images showed a lingually expanded cortical plate associated with the lesion, but the buccal cortical plate was perforated. The mandibular canal was identified inferior and lingual to the lesion (). A provisional diagnosis of odontogenic keratocyst was made, and the lesion was excised with the extraction of the involved tooth. The histopathological diagnosis proved to be an odontogenic keratocyst with chronic inflammation and a foreign body reaction, and the cyst wall showed periosteum adhesion.