Keratoacanthoma that is named Infundibular Keratinizing Acanthoma is a benign tumour showing differentiation to the squamous epithelium of the follicular isthmus. A 2.5-year old Canary referred to small animal hospital of Tehran Veterinary faculty. the owner main compliant was the presence of a mass on the leg of the animal. In physical examination, there was a huge mass with the diameter of 3 * 3 cm on the proximal area of left leg. Palpation of the mass showed that the mass was with the soft tissue density and moveable. Radiography didn't showed any document of metastasis in lung tissues or any disorders other than the mass. Animal referred to the surgery and anesthetized with the ether. The mass successfully removed.The mass referred to the pathology. In pathologic examination of the samples, stratified squamous keratinizing epithelium with intracytoplasmic keratohyalin granules the tumor was extended into the dermis and sub cutis. Pathologic assessment confirmed Kerato acanthoma.