TY - CHAP M1 - Book, Section TI - Squamous Cell Carcinoma and Keratoacanthoma A1 - Lonsdorf, Anke S. A1 - Hadaschik, Eva N. A2 - Kang, Sewon A2 - Amagai, Masayuki A2 - Bruckner, Anna L. A2 - Enk, Alexander H. A2 - Margolis, David J. A2 - McMichael, Amy J. A2 - Orringer, Jeffrey S. PY - 2019 T2 - Fitzpatrick's Dermatology, 9e AB - AT-A-GLANCESquamous cell carcinoma (SCC) is the second most common skin cancer, after basal cell carcinoma, in immunocompetent white individuals, and the most common skin cancer in immunosuppressed organ transplantation recipients worldwide.SCC development in the skin is considered a multistep process, most invasive SCCs develop from preinvasive lesions or in situ tumors such as actinic keratosis or Bowen disease.Risk factors for SCC include ultraviolet (UV) radiation, genetic predisposition, physical and chemical carcinogens, immunosuppression, drugs, viral infection, chronic inflammation, and chronic injury of the skin.Diagnosis of SCC is established histologically. Histologic subtypes include spindle-cell, acantholytic, verrucous, and desmoplastic SCCs, and keratoacanthoma.High-risk features for local recurrence and the development of metastatic disease include >2 mm thickness; Clark level higher than IV; perineural invasion; lip or ear as primary site; poorly or undifferentiated tumor.The primary mode of therapy for localized SCC is complete surgical excision, preferentially microscopically controlled surgery (Mohs surgery). Nonsurgical interventions include topical therapy, and for locally advanced, unresectable or metastatic SCC, radiation therapy and systemic treatment with chemotherapy or targeted therapy.Primary prevention for the development of SCC is based on decreasing UV radiation exposure and concomitant risk factors, and the effective treatment of precursor lesions. Systemic retinoids, niacinamide, as well as change of the immunosuppressive regimen in solid-organ transplantation recipients may be options for the secondary prevention of SCC in high-risk patients. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/11/01 UR - accessmedicine.mhmedical.com/content.aspx?aid=1161335469 ER -