A repeatedly recurrent desmoplastic ameloblastoma after removal and allobone graft: Radiographic features compared with histological changes
A 40-year-old man visited the Chosun University Dental Hospital with a tender swelling on his anterior palatal area. The overlying mucosa appeared normal and all the teeth in the affected area were caries free and reacted positively to both thermal and electrical stimuli. His medical history was non-contributory.\nA panoramic radiograph revealed a multilocular and mixed radiolucent/radiopaque expansile lesion extending from the right second premolar to the left canine of the maxilla, presenting a soap bubble appearance in the middle third of the lesion, and ill-defined radiopacity in the left third of the lesion (). The lesion showed an often curved and scalloped border extending to the middle portion of the roots of the upper anterior teeth. The lesion was diagnosed provisionally and radiographically as ameloblastoma with histological evidence of a developmental cyst showing a cystic structure lined by epithelium with incisional biopsy (). After endodontic treatment of multiple upper anterior teeth, he underwent enucleation of the lesion and an allobone graft by an oral surgeon. Histopathologically, the enucleated mass showed unicystic ameloblastoma with peripheral palisading of hyperchromatic epithelium and loose fibrous stroma (). The fistula formation process near the bone graft area was persistent. After being treated repeatedly with antibiotics and dressing for about 5 months, he finally underwent removal of the allobone.\nFour years after the first surgery, a recurrent tumor was found in the same area. A panoramic radiograph showed a unilocular cystic radiolucency in the area corresponding to the right part of the primary lesion (), and re-enucleation of only the cystic lesion and Tutoplast grafting were performed. Histopathologically, the enucleated mass had changed from a developmental cyst to the desmoplastic type of ameloblastoma that contained small islands and thin cords of ameloblastic epithelium within a dense fibrous connective tissue stroma ().\nThe patient returned with the symptom of mild pain at the site of the operation 5 years after the second surgery. A panoramic radiograph revealed a soap bubble appearance in the periapical area of the right first and second molars (). On the axial cone-beam computed tomographic (CBCT) images, multiple small cyst-like structures were found adjacent to the maxillary sinus and in the anterior area, which were separated by normal bone. The lesion at the molar area was well demarcated from the maxillary antrum (). Sagittal CBCT images showed small loculations in the molar and anterior area, respectively, and they were separated by normal bone (). The tumor showed a relatively defined border, and it was adjacent to the maxillary sinus ().\nFinally, the tumor histology became a follicular pattern next to the desmoplastic type that contained small cystic tumor islands and thin cords of ameloblastic epithelium within connective tissue stroma ().