Ameloblastic fibro-odontosarcoma is an extremely rare subtype of odontogenic sarcoma, with only 13 cases reported in the literature.

A 4-year-old male presented with a painless mandibular swelling, which appeared 4months previously. Cone beam computed tomography revealed an extensive, ill-circumscribed, multilocular radiolucency of the right mandible extending from the first deciduous molar to the ramus with slightly dense opacities. Histological examination of the incisional biopsy specimen revealed a biphasic tumor with sarcomatous mesenchyme and benign ameloblastic epithelial component compatible with a diagnosis of ameloblastic fibrosarcoma. A right hemimandibular resection was performed. Areas of deposition of dentinoid and enamel material closely adjacent to ameloblastic epithelium were noted in the excised specimen. A final diagnosis of ameloblastic fibro-odontosarcoma was made. After four years of close follow-up, there is no sign of recurrence or metastasis.

Although rare, ameloblastic fibro-odontosarcoma should be considered in the differential diagnosis of jaw lesions with radiographic radiolucencies exhibiting poorly circumscribed outlines and containing radiopaque material. Definite diagnosis depends on histopathological examination. Complete surgical excision is the treatment of choice.