Tumors are abnormal growths of tissue that can be benign or malignant. Any tumors that form on the eyelid should be evaluated and treated as quickly as possible, and cancerous tumors typically require immediate medical attention. Even a benign tumor can cause pain or damage to the eye, such as blocking the tear ducts or preventing the eyelids from closing. A biopsy will usually determine whether the eyelid tumor is benign or malignant.