Unicystic ameloblastoma

Unicystic ameloblastomas are a rare variant of ameloblastomas, which usually occur in younger populations. They are characterized by slow growth and being relatively locally aggressive, with the main site of origin being the posterior portion of the mandible. Late recurrence following surgical management is relatively common and is related to the histological type, the site of origin, and the initial treatment modality. This case report describes a unicystic ameloblastoma occurring in the right posterior mandible of an 8-year-old girl. She presented with progressive swelling of the right lower deciduous molar region for 3 months. Panorex imaging showed a well-defined unilocular radiolucency surrounding the impacted permanent first molar, root resorption of the deciduous second molar, and mesial displacement of the partially formed second bicuspid. Computed tomography revealed expansion of both buccal and lingual cortical plates of the right posterior mandible by the cystic lesion with inclusion of the permanent lower first molar. It was initially diagnosed as a dentigerous cyst and was treated by enucleation and removal of the permanent first molar and the deciduous second molar. The partially formed second premolar and the permanent second molar were left undisturbed. A histopathological examination of the specimen showed a mural variant of a unicystic ameloblastoma. After surgery, healing of the right mandibular bone defect was uneventful, as shown by follow-up panoramic radiography. No recurrence was detected at an 18-month follow-up. We suggest that the long-term follow-up is mandatory because late recurrence of unicystic ameloblastomas has been reported.