Ameloblastic fibromas and related tumors in cattle.

This article concerns rare odontogenic tumors that occur predominantly in the mandibular incisor region of young cattle and which have often in the past been referred to as ameloblastomas, or as the outdated synonym, adamantinoma. Twenty-two examples from the literature and two new ones were studied. Six consisted of epithelial islands which resembled those of ameloblastoma but which were located within a cellular fibrous connective tissue that was the second component of the tumor; these mixed odontogenic tumors therefore represented ameloblastic fibromas, not ameloblastomas. Eight consisted of a combination of ameloblastic fibroma and odontoma and therefore were ameloblastic fibro-odontomas, and one was apparently malignant (ameloblastic fibro-odontosarcoma). Excluding this last lesion, these tumors should respond well to enucleation, like their human counterparts but, to confirm this hypothesis, the margins of future examples should be carefully examined to determine that they are well-demarcated, not invasive. The microscopic features of the remaining 9 tumours could not be evaluated adequately, while another 17 tumors in cattle and water buffalo reported briefly could not be studied to any extent because of insufficient information.