Metachronous ameloblastic fibro-odontoma and dentigerous cyst in the posterior mandible.

An ameloblastic fibro-odontoma (AFO) is a rare mixed odontogenic tumor with histologic features of an ameloblastic fibroma in conjunction with the presence of dentin and enamel. It usually appears as a well-circumscribed radiolucency with radiopaque foci and slow growth and is commonly seen in children and young adults. A 13-year-old boy presented with an asymptomatic swelling in the posterior right region of the mandible and the right ascending ramus. The clinical, imaging, and histopathologic findings confirmed the diagnosis of an AFO. After 8 months, a radiolucent lesion involving the unerupted mandibular left third molar was observed; a final diagnosis of a dentigerous cyst (DC) was established for this lesion. Although coincidental events, metachronous odontogenic lesions suggest a possible common genetic origin, since both can be caused by related cellular signaling pathways. Complete enucleation is recommended for both AFOs and DCs; rates of recurrence are low.