Among skin cancers, basal cell carcinoma (BCC) is considered as a relatively indolent disease. Sometimes, these carcinomas have an unusual clinical behaviour, with extreme aggressiveness. Based on reports of eight cases of aggressive BCC of the head and neck areas, and after a review of the literature, we define three criteria of aggressiveness: (1) initial diameter greater than 1 cm, (2) more than two recurrences despite all tentative conclusions of adequate treatment, or (3) extension into any extracutaneous structure.