Ameloblastic fibro-odontosarcoma with mandibular bone invasion and regional lymph node metastasis in a cat: case report.

Odontogenic tumours are uncommon neoplasms in domestic animals, mostly solitary and locally infiltrative, but rarely metastatic. We report the case of a 13-year-old neutered male cat presented with a mandibular gingival neoformation. A computed tomography scan revealed an irregular neoformation with marked post-contrast enhancement, associated with lysis of the incisive bone and mandibular symphysis. Histologically, the oral mucosa and mandibular bone were infiltrated by a neoplasm consisting of a mixed population of odontogenic epithelium admixed with bundles of odontogenic ectomesenchyme, multifocally associated with hard tissue deposition. A spindloid cell component had metastasized to the right mandibular lymph node. The epithelial component was immunoreactive for cytokeratins (CK) 5/6, CK 14, pancytokeratin (CK AE1/AE3) and p63; the ectomesenchymal component was vimentin positive. A final diagnosis of ameloblastic fibro-odontosarcoma with bone invasion and lymph node metastasis was made. The findings indicate the metastatic potential of this rare tumour.