Skin cancer involves the uncontrolled growth of abnormal cells in the skin layers. It is primarily caused by excessive exposure to ultraviolet radiation, which can damage the DNA in skin cells, leading to malignant transformation. There are several distinct types, including basal cell carcinoma, squamous cell carcinoma, and melanoma, each arising from different skin cell types. Diagnosis is typically established through visual inspection and histopathological examination of tissue samples. Treatment varies depending on the specific type and stage of the malignancy but commonly includes surgical excision, topical treatments, or immune-modulating therapies designed to remove the cancerous tissue and prevent local recurrence.