Ameloblastic fibro-odontoma––report of two cases with ultrastructural study of tumour dental hard structures

Abstract Two cases of ameloblastic fibro-odontoma (AFO) are reported. Both cases occurred in boys, aged 11 years (case 1) and 9 years (case 2). In case 1 a large mixed radiolucent and radiopaque lesion was observed in the angle of the left mandible. In case 2 with involvement of the left mandibular angle a well-defined translucency was seen without any noticeable calcifications. Both tumours were enucleated. Case 1 revealed the histologic characteristic of an AFO. One part of the tumour consisted of cementoid globules with Sharpey fibre-like structures at their periphery. Electron microscopy revealed areas representative of dentinal tubules. At the periphery connective fibres showed signs of initial calcification. Case 2 showed features of an immature AFO. Further ultrastructural studies are needed to define in more detail the mineralising structures of AFO.