Rehabilitation with dental implants is an effective method of treating edentulous patients, but carries a risk of complications such as peri-implant mucositis and peri-implantitis. Progressive local inflammation of the periimplant tissues can spread beyond the bone, in rare cases leading to the development of an extraoral fistula. When diagnosing an extraoral fistula within the craniofacial region, a comprehensive differential diagnosis should be considered, including odontogenic and implant-prosthetic aetiologies. Early identification of the actual source of infection and the implementation of targeted treatment will promote rapid healing of the lesions, preventing invasive and burdensome procedures in general surgery or dermatology. This paper describes the case of a patient with a chronic, non-healing skin lesion caused by complicated peri-implantitis beneath a cement-retained prosthetic restoration resulting in an extraoral fistula. Radiological diagnosis enabled the identification of an inflammatory lesion around the implant at 31 and the implementation of appropriate treatment, which involved the explantation of the causative implant. The treatment successfully led to bone tissue regeneration and complete healing of the extraoral fistula.