Invasive squamous cell carcinoma of the skin

Core Messages: Squamous cell carcinoma (SCC) of the skin is an invasive, malignant neoplasm arising from the keratinizing cells of the suprabasilar epidermis or epidermal appendages. SCC and basal cell carcinoma (BCC) comprise the majority of nonmelanoma skin cancers (NMSCs), and together they account for the most common malignancy worldwide. SCC represents a histo-logical and clinical evolutionary spectrum of disease, ranging from preinvasive cases of actinic keratosis and Bowen's disease (SCC in situ) to frankly invasive SCC. As the subject of preinvasive SCC is covered in the preceding portion of this text, the present section focuses on the clinical features, diagnosis, and management of the various forms of invasive cutaneous SCC. Excision remains the treatment of choice, although radiotherapy, intralesional, or topical chemotherapy, and topical immunomodulatory therapy may prove effective in selective cases.