Squamous cell carcinoma, also known as epidermoid carcinoma, primarily originates from the skin covered by squamous epithelium. The eyelid margin, where the skin and conjunctiva meet, is a common site for its occurrence. This type of cancer is more malignant than basal cell carcinoma, progresses more rapidly, and causes greater destruction. It can destroy ocular tissues, invade the paranasal sinuses or intracranial cavity, and can also metastasize through lymphatic vessels to the preauricular or submandibular lymph nodes, potentially leading to systemic metastasis.