Skin cancer is the most common malignancy worldwide, primarily comprising basal cell carcinoma and squamous cell carcinoma. The incidence in Asia has been increasing year by year. Most cases can be cured by outpatient surgery; however, if diagnosis and treatment are delayed, the disease may cause local invasion or even metastasis.
· Sunlight and artificial ultraviolet (UV) radiation exposure (the most important risk factor)
· Fair skin and history of recurrent sunburn
· Long-term immunosuppressive therapy
· Advanced age
· Chronic arsenic exposure
· Chronic non-healing ulcers and scars
Ultraviolet radiation induces the formation of pyrimidine dimers, leading to TP53 gene mutations, while also causing local immunosuppression. In immunocompromised individuals, inadequate clearance of mutated cells significantly increases the risk of developing cutaneous squamous cell carcinoma and other skin cancers.
Basal cell carcinoma often presents as a pearly, translucent nodule with telangiectasia and central ulceration. Squamous cell carcinoma typically appears as a rough, indurated plaque with a verrucous or necrotic, ulcerated surface. Both types predominantly occur on sun-exposed areas such as the head and face.
Dermoscopy improves diagnostic accuracy. Full-thickness excisional skin biopsy confirms the diagnosis. Sentinel lymph node biopsy may be considered for high-risk squamous cell carcinoma. Imaging is used in patients with evidence of lymph node or perineural involvement.