A unique case of desmoplastic ameloblastoma of the mandible - Report of a case and brief review of the English language literature

A unique case of desmoplastic ameloblastoma is reported from the clinical, radiographic, and histologic viewpoints. The patient was a 56-year-old man who complained of a painless swelling on the buccal aspect of the left mand ible. Periapical and panoramic radiographs revealed a rounded, slightly rad iolucent area with blurred osteosclerotic margins. Occlusal radiograph and computed tomography images disclosed buccal bone expansion outlined by thin ned cortices. Computed tomography images exhibited an enhanced area in the anterior portion of the lesion. Interestingly, the coronal computed tomogra phy images revealed a close relationship between the periodontal membrane o f the left mandibular second premolar and the enhanced area. Biopsy specime ns from the anterior portion of the lesion displayed typical histologic fea tures of the desmoplastic variant of ameloblastoma. However, those from the posterior portion disclosed a large cystic formation. Oxytalan fibers were identified in the stromal tissue of the tumor, which suggested that the tu mor arose from the epithelial rests of Malassez in the periodontal membrane of the related tooth. We also reviewed previously reported 41 cases. In 36 of 38 cases in which the location was specified, the tumor was found in th e anterior to premolar region of the maxilla or mandible. A radiographic de scription was given in only 29 previous cases, 28 of which involved multilo cular lesions. No cyst as large as the one in the present case was found am ong the previously reported desmoplastic ameloblastomas. Although the prese nt case deviates from the usual desmoplastic variant of ameloblastoma in te rms of locus, radiologic appearance, and cyst formation, it still meets the histologic criteria for this variant in both the stromal and epithelial co mponents.