Multilocular Unicystic Ameloblastoma of Mandible

Introduction. We report a rare case of unicystic ameloblastoma (UA) of mandible which showed multilocular radiolucency on the left side of mandible on radiographic examination which is very unusual, and the majority of the cases of UAs till date has been reported of unilocular radiolucency. On histopathological examination, an odontogenic cystic lining that proliferates that intraluminally resembling ameloblastomatous epithelium was observed, leading to a definitive diagnosis of unicystic ameloblastoma. Case Presentation. A 42-year-old male patient presented with a swelling on the left side of the mandible extending from 33 to 36. Radiographically, it showed a multilocular radiolucent lesion resembling odontogenic cyst; however, the final diagnosis was made on histopathological ground with the inclusion of radiological and clinical features. Conclusion. It can be concluded that at present, histopathologic examination is the most sensitive tool for differentiating between odontogenic cysts and UAs. However, both clinical and radiologic findings share equal contribution to the final diagnosis. 1. Introduction Ameloblastomas are benign tumors whose importance lies in its potential to grow into enormous size with resulting bone deformity. They are typically classified as unicystic, multicystic, peripheral, and malignant subtypes [1]. A solid or multicystic ameloblastoma is a benign epithelial tumor of odontogenic origin showing a strong tendency to recurrence and local aggression. Solid/multicystic, peripheral, desmoplastic, or unicystic ameloblastomas are other subtypes of ameloblastoma [2, 3]. Unicystic ameloblastoma (UA) represents an ameloblastoma variant, presenting as a cyst [3]. In 1977, Robinson and Martinez first used the term “unicystic ameloblastoma” (UA) for such lesions [4], but it was adopted in the second edition of the international histologic classification of odontogenic tumors by the WHO in 1992 [5]. The other name as recognised by WHO is “cystogenic ameloblastoma” [3]. Five to 15% of all ameloblastomas are of the unicystic type. Cases associated with an unerupted tooth show a mean age of 16 years as opposed to 35 years in the absence of an unerupted tooth. The mean age is significantly lower than that for solid/multicystic ameloblastoma. There is no gender predilection [3]. Unicystic ameloblastoma (UA) is a prognostically distinct entity. It has a recurrence rate of 6.7–35.7%, and the average interval for recurrence is approximately 7 years. Six radiographic patterns have been identified for UA, ranging from well-defined unilocular to