A 7-year-old, neutered male, mixed breed dog presented to Cornell's Community Practice Service in July 2016 for his annual physical exam and vaccines as well as evaluation of an oral mass that his owners had noticed I week prior. The owners reported that the mass did not appear to cause the dog pain and they had not noticed any bleeding fom the oral cavity. The patient's appetite remained normal. Upon presentation, physical exam was within normal limits except for a BCS of 8/9 and a pink, irregular, non-ulcerated gingival mass. A complete blood count, serum biochemistry, and urinalysis were performed. The patient was referred to the Dentistry and Oral Surgery Service for further work-up of the oral mass. The patient was presented to the Dentistry and Oral Surgery Service I month later in August 2016 for evaluation of his oral mass. The physical exam remained unchanged from previously, except for a palpably enlarged left mandibular lymph node. Fine needle aspirates were taken from both mandibular lymph nodes. The patient was placed under general anesthesia. A thorough oral examination as well as periodontal treatment and dental radiographs were performed. An incisional biopsy of the mass was obtained and submitted for histopathology. The mass was diagnosed as a canine acanthomatous ameloblastoma (CAA). Imaging of the head and thorax using CT were performed. The patient returned two weeks later for en bloc surgical resection of the mass by mandibular rim excision. This case report will discuss diagnosis, treatment, and prognosis of CAA and will detail the surgical procedure of a mandibular rim excision.