Ameloblastic fibrosarcoma in a bull

This report describes a malignant odontogenic neoplasm in a 7-year-old bull. The mass, involving the right mandible, was locally invasive and destructive. Histologically, it consisted of islands and cords of benign odontogenic epithelium, entrapped in a population of malignant mesenchymal cells. These morphological features are characteristic of ameloblastic fibrosarcoma in man, an odontogenic tumour not previously described in animals.