TY - CHAP M1 - Book, Section TI - The Skin and Subcutaneous Tissue A1 - Harbour, Patrick A1 - Song, David H. A2 - Brunicardi, F. Charles A2 - Andersen, Dana K. A2 - Billiar, Timothy R. A2 - Dunn, David L. A2 - Kao, Lillian S. A2 - Hunter, John G. A2 - Matthews, Jeffrey B. A2 - Pollock, Raphael E. PY - 2019 T2 - Schwartz's Principles of Surgery, 11e AB - Key Points The epidermis consists of continually regenerating stratified epithelium, and 90% of cells are ectodermally derived keratinocytes.Pilosebaceous units are lined by the germinal epithelium of the epidermis and thus serve as an important source of epidermal regeneration after partial-thickness injury or split-thickness skin graft. Dermal fibers are predominantly made of type I and III collagen in a 4:1 ratio. They are responsible for the mechanical resistance of skin. The drugs most commonly associated with epidermal necrolysis include aromatic anticonvulsants, sulfonamides, allopurinol, oxicams (nonsteroidal anti-inflammatory drugs), and nevirapine. In wounds being allowed to heal secondarily, negative pressure wound therapy can increase the rate of granulation tissue formation. Staphylococcus aureus is the most common isolate of all skin infections. Impetigo, cellulitis, erysipelas, folliculitis, furuncles, and simple abscesses are examples of uncomplicated infections, whereas deep-tissue infections, extensive cellulitis, necrotizing fasciitis, and myonecrosis are examples of complicated infections. Hemangiomas arise from benign proliferation of endothelial cells surrounding blood-filled cavities. They most commonly present after birth, rapidly grow during the first year of life, and gradually involute in most cases. Basal cell carcinoma represents the most common tumor diagnosed in the United States, and the nodular variant is the most common subtype. The natural progression of basal cell carcinoma is one of local invasion rather than distant metastasis. Squamous cell carcinoma is the second most common skin cancer, and typically arises from an actinic keratosis precursor. Primary treatment modalities are surgical excision and Mohs microsurgery. Cautery and ablation, cryotherapy, drug therapy, and radiation therapy are alternative treatments. Tumor thickness, ulceration, and mitotic rate are the most important prognostic indicators of survival in melanoma. Sentinel lymph node biopsy is often used to stage individuals with biopsy-proven high risk melanoma and clinically node-negative disease. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1164309552 ER -