A squamous cell carcinoma

This cancer may appear as a growing lump, often with a rough surface. It can appear as a thickened, red, scaly bump or wart-like growth. It may even appear as a raised crusted sore.

Squamous cell carcinomas are more likely to invade tissues beneath the skin, and are slightly more likely to spread to distant parts of the body than are basal cell carcinomas. Even so, few squamous cell skin carcinomas spread to the lymph nodes or other organs.

Bowen's disease

Bowen's disease is squamous cell carcinoma in situ. “In situ” means it is still only in the top part of the skin (the epidermis) and has not spread beyond the area in which it started. Bowen's disease is the earliest form of squamous cell skin cancer. Bowen's disease appears as reddish, scaly patches.

Bowen's disease of the anal and genital skin is often related to the human papillomavirus (HPV), a sexually transmitted infection that can also cause genital warts.