Squamous cell carcinoma with sarcomatous stroma in the nasal cavity of a dog

This is a report of an unusual squamous cell carcinoma in the nasal cavity of a dog. A 13‐year‐old Golden Retriever was presented with a unilateral nasal and ocular discharge. Although a nasal tumour was suspected, initial diagnostic investigations were unrewarding, and, with worsening clinical signs, the dog was euthanased. Necropsy examination confirmed the presence of a nasal tumour that was composed histologically of both a well‐differentiated squamous cell carcinoma component blending with a predominant spindle cell component. Immunohistochemical staining with anti‐human keratin/cytokeratin (AE1/AE3, CAM 5.2 and broad spectrum cytokeratin), Vimentin, Desmin, smooth muscle actin and S‐100 protein supported a diagnosis of a squamous cell carcinoma with (pseudo) sarcomatous stroma.