Squamous cell carcinoma is a cancer of the skin.
Exposure to sunlight is one trigger-factor for this cancer and it is seen more commonly in white cats, and cats living in hot sunny countries.
The tumour commonly affects the nose or the ears and can initially look like a small scratch or wound that won't heal. Spread (metastasis) of these tumours is uncommon but local lymph nodes are sometimes affected.
Early treatment of these tumours can be very successful and most commonly involves surgical removal or radiation therapy. For some tumours affecting the superficial layers of the skin local radiation therapy (brachytherapy, applied via a probe touched onto the skin) can be very effective.
The response to drug therapy (chemotherapy) is generally not very good but for some affected cats, an alternative to conventional surgery may be 'cryosurgery' where the affected tissue is frozen using liquid nitrogen applied via a special probe. However, conventional surgery and/or radiation therapy are usually the preferred options.