Final answer:
The AIS code assigned to a specific skin lesion that is unknown or not required is 'C80.XX' in the International Classification of Diseases for Oncology (ICD-O-3).
Step-by-step explanation:
The AIS is a scoring system used to classify and describe the severity of injuries. It is intended for use in research and to help in the management and prognosis of trauma patients. If a specific skin lesion is unknown or not required, the AIS code that is assigned is 'C80.XX'. The 'C80' category is used for 'Malignant (Primary) neoplasms without specification of, or as a secondary tumour of, the breast, female genital organs or urinary tract' in the International Classification of Diseases for Oncology (ICD-O-3). Since the specific skin lesion is unknown or not required, the code 'XX' is assigned to represent this uncertainty.