Desmoplastic ameloblastoma (DA) and Ameloblastic fibroma (AF) show common histopathologic features such as enamel organ like epithelial islands or cords on the background of abundant fibrous stroma. Despite their similar histopathologic features, it was reported that they have different pathogenesis and clinical behavior. The purpose of this study was to rev iew clinicopathologic features of DA and AF among Korean subjects. 7 cases of DA and 4 cases of AF were retrieved from the files of Seoul National University Dental Hospital (SNUDH), and their clinical features, radiographic findings, and histopathologic features were reviewed and compared. DA occurred in 3 males and 4 females. They occurred from 24 to 62 years of age, showing the mean age of 42.7 years. 5 of the 7 tumors occurred in the maxilla, and all of them in the anterior region, showing predilection for the maxillary anterior regions. There was no recurrence. Radiographically, they showed well demarcated unilocular or multilocular radiolucency. AF occurred in 5 males and 2 female. They occurred from 6 to 29 years of age, showing the mean age of 14 years. All tumors occurred in the mandibular molar area. Recurrence was recognized in 1 case. Although DA and AF showed similar histopathologic features, they showed different clinical behaviors. While DA showed predilection for the anterior maxilla, AF did for posterior mandible. While DA occurred mainly in adults, AF did in adolescents. Recurrence was recognized not in DA but in AF. Therefore, DA and AF should be differentiated from each other in spite of similar histopathologic findings

Desmoplastic ameloblastoma(DA) is histologically characterized by extensive stromal collagenization or desmoplasia. ln this study, anti-cytokeratin 8/18, 13, 19 for pathogenesis as well as anti-PCNA for cellular proliferation, were used to det ect the expression of these proteins in the desmoplastic ameloblastoma Basal layers of tumor nest were negatively stained by CKl3, while suprabasal and inner cells were positive for CK13. CK8/18 and CK 19 was negatively stained in the peripheral portion of tumor nest in DA, whereas CK 8/18 was in central portion and CKl9 was positive in the su prabasal and some of central portion of the cel l nest. PCNA index of DA was 60 ::!: 14.6% to 95 ::!: 17 .2%. The peripheral tumor cells of the islets presented higher PCNA labeling index, while some cells in the central area of foll icle containing squamous like cells also presented negative PCNA labeling index. Especially tumor islands showed higher PCNA index than in main tumor mass. lt suggested that desmoplastic ameloblastoma might be composed of many different tumor cell types‘ and have hi gher pr이 ife r a ting activity in tumor islands of the desmoplastic stroma