Aggressive granular cell ameloblastoma arising from radicular cyst: a case report of an unusual variant and a public health concern

Background: Ameloblastoma is the second most common odontogenic tumor and categorized into various clinical and histopathological types. They are found exclusively in the mandibular posterior region, mainly between third and fifth decades of age. However, granular cell ameloblastoma is a unique and rare histologic variant of unicystic/multicystic ameloblastoma. Although it is rare, it has greater recurrence potential and chances of malignant potential. Case Description: A 75-year-old male patient reported to a dental clinic with a slow growing swelling in the right side of posterior jaw region in the last 7 months. On questioning, he reveled a history of radicular cyst enucleation in the same region almost 3 years back. On intraoral examination, the swelling seems originating from #46 region and extended posteriorly to involve retromolar area. Furthermore, a purulent discharge was observed on compression along with bicortical expansion. A straw-colored fluid was withdrawn from the swelling. Panoramic and cone beam computed tomography (CBCT) examination revealed a homogenous, multilocular radiolucent lesion with bicortical expansion. Later, histopathological examination displayed features of a granular cell ameloblastoma. The paper describes the clinical presentation, radiographic and histopathologic features along with the treatment. Additionally, rarity of the case is discussed while comparing it with previously reported cases of ameloblastoma arising from the radicular cyst. Conclusions: Clinical, radiographic and histopathological combined interpretation is essential in every case of oral pathology for final diagnosis. Immunohistochemistry is important in many aspects to rule out behavioral changes in the pathological entity.