Cutaneous horn and squamous cell carcinoma in situ (Bowen's disease) in a cat.

Cutaneous horn and squamous cell carcinoma (SCC) in situ (i.e., Bowen's disease) were documented concurrently in a cat. The cat had multiple, crusted lesions and a cutaneous horn on the right dorsal lumbar area. All the crusted cutaneous lesions were diagnosed as SCC in situ. Other findings included the presence of a thymoma and hepatoma. This cat was tested, and results were negative for feline leukemia and feline immunodeficiency viruses. At necropsy (eight months after the initial diagnosis was made) the hepatoma had ruptured, resulting in exsanguination and death.