Cutaneous squamous-cell carcinoma (cSCC), also known as squamous-cell carcinoma of the skin or squamous-cell skin cancer, is one of the three principal types of skin cancer, alongside basal-cell carcinoma and melanoma.[10] cSCC typically presents as a hard lump with a scaly surface, though it may also present as an ulcer.[1] Onset and development often occurs over several months.[4] Compared to basal cell carcinoma, cSCC is more likely to spread to distant areas.[11] When confined to the epidermis, the outermost layer of the skin, the pre-invasive or in situ form of cSCC is termed Bowen's disease.[12][13]

Reference
Wiki: Cutaneous squamous cell carcinoma