What is Squamous Cell Carcinoma (SCC)? Squamous Cell Carcinoma (SCC) is a malignant tumour arising from the squamous epithelium—the flat, thin cells that cover the skin and line body cavities (e.g., the oral cavity and nasal planum) and form areas such as paw pads, nail beds, ears , and eyelids. Squamous cell carcinoma (SCC) is one of the most common malignant tumours in cats. It is locally aggressive, often destructive, and, in advanced cases, life-threatening (Murphy, 2013