Squamous cell carcinoma, also known as squamous cell carcinoma, originates from keratinocytes in the epidermis and its appendages (hair follicle infundibulum, sebaceous gland ducts, and terminal sweat ducts), and is prone to occur in exposed areas such as the scalp, face, neck, and back of the hands. It may present as ulcers in the early stages, and is often secondary to chronic ulcers or chronic sinus openings, or ulcers in scars that do not heal for a long time and become cancerous. Clinically, it may present as a cauliflower shape, with irregular raised edges, an uneven bottom, and easy bleeding, often accompanied by infection and foul odor. There may be local infiltration and regional lymph node metastasis. In the lower limbs, it is often accompanied by osteomyelitis or periostitis.