A 6 year old female-spayed Collie presented to me in September of 2013 with a growth in the mouth, right out in front of the left incisors. It didn’t respond to initial antibiotic and anti-inflammatory therapy, so surgery was scheduled to get a biopsy.
The result: Acanthamatous amelobastoma
From IDEXX Laboratories:
Oral mucosa: The submucosa is expanded by an unencapsulated, invasive mass composed of anastomosing cords and broad sheets of polygonal cells and a prominent peripheral layer of palisading columnar cells within a minimal fibrovascular stroma. Neoplastic cells have distinct cell borders, abundant eosinophilic cytoplasm, and prominent intercellular bridging. There is mild anisocytosis and anisokaryosis. Nuclei are round to oval with vesicular chromatin. Lesional tissue extends to the apparent deep margin of the submitted specimen.
Acanthomatous ameloblastoma (acanthomatous epulis) has an aggressive local behavior and frequently invades the bone of the underlying mandible or maxilla. Golden Retrievers, Akitas, Cocker Spaniels, Shetland Sheepdogs, and Old English Sheepdogs are predisposed. The mean age at presentation is 7-10 years, and sex predisposition is unlikely. The rostral mandible is the most common site. They do not metastasize.
At the time, we spoke about rechecking in 4 to 6 weeks. It did, in fact, return and it was angry. Her owner brought a study to my attention using a chemotherapy drug called Bleomycin. As I’m not an oncologist, and I rarely get into advanced chemotherapy beyond prednisone for Lymphoma, this treatment was news to me, and I happily read the study. The survival times looked encouraging, but when I got to the part about adverse effects, I thought some of them were a little startling.
Adverse effects were limited to wound formation with bone exposure (n = 4), mild tissue reactions (n = 3), local swelling (n = 2) and local infection (n = 1)
The small sample size was also noteworthy. Not much is known about how this form of cancer responds to treatment… any treatment or combination of treatments.
After a conversation with the owner, and some thought on his part, he decided to move forward. We committed to 6 weekly treatments. The anesthetic protocol and Bleomycin administration protocol was strictly followed, we needed to reach for antibiotics on some occasions, and we stayed the course for 6 treatments. Follow the progression of photographs below.