Squamous cell carcinoma in an American bison (Bison bison bison).

The following case report is, to the best of our knowledge, the first documentation of a squamous cell carcinoma in a full-blooded American bison (Bison bison bison). This female bison developed an ulcerated lesion on the left flank, at the site of a brand, in the summer of her eighth year. In the winter of her ninth year, as the lesion continued to grow, a biopsy was performed, and a diagnosis of squamous cell carcinoma was made. Ultimately, there was metastasis to the liver, a lung, and a prefemoral lymph node.