A large ameloblastic fibro - odontoma in the mandible

A 47-year-old man had a history of progressive mandibular swelling for 15 years and increasing quickly in size for 4 years. Physical examination revealed a hard immobile mass in the mandibular region, with multiple ulcers of varying sizes (Figure 1A). The well-demarcated mass measured 20 cm × 12 cm. The patient had impediment of speech, salivation and poor oral hygiene, with defect of dentition in the mandible. Coronal CT showed a well-circumscribed expansile mass with multiloculated scrotiform osteolytic lesions in the mandible (Figure 1B). Axial CT showed the mass included linear and patchy calcification and ossification (Figure 1C). CT 3D reconstruction revealed the mandible appeared honeycombed (Figure 1D). On T1W and T2W MR images, cystic low density components on CT appeared high signal, while calcification and ossification appeared low signal (Figure 1E, 1F). The resected mass was a well-defined encapsulated neoplasm containing teeth. Macroscopic section of the tumor showed both cystic and solid component. Brown colored viscous liquid was seen in the cystic cavities, while the solid component was bone (Figure 1G). Microscopically, the tumor was composed of ameloblast cells and fibrous tissue. Calcification and matured bone trabecula were found within some fibrous tissue (Figure 1H).

Figure 1 A: Physical examination reveals a large hard mass in mandibular region with multiple ulcers on the surface; B: Coronal CT in soft tissue window shows multicystic oestolytic lesions in the mandible; C: Axial CT in a bone window shows linear and patchy calcification and ossification in the mass; D: CT 3D reconstruction reveals honeycombed mandible; E, F: On T1W and T2W MR images, cystic low-density components on CT appear high signal, while calcification and ossification appear low signal; G: Macroscopically, the tumor section appears honeycombed, with both cystic and solid components; H: Microscopically, the tumor is composed of ameloblast cells and fibrous tissue

Acknowledgements

Disclosure: The authors declare no conflict of interest.