The aim of this study was to report a rare case of inflammatory retrograde peri-implantitis caused synergistically by two foreign bodies and associated with implant malposition. Inflammatory retrograde peri-implantitis is manifests as a clinically symptomatic periapical lesion that develops shortly after implant insertion and is characterized by bone loss around the apex of the implant caused by microbial activity, while the coronal portion shows normal osseointegration. To elucidate the presence of a bluish nodular lesion with a central pink dot located at the apex of a dental implant in the right maxilla of a female patient, clinical assessment and tomographic and histological analysis examinations were performed. The tests revealed the presence of exogenous material compatible with gutta percha and rubber mold material inside the lesion. The lesion exhibited an aggressive appearance and rapid progression that caused the loss of bone support around the implant within approximately 6 months. These findings indicated an exacerbated inflammatory lesion with a high potential for bone destruction and resorption around the dental implant, which led to the diagnosis of inflammatory retrograde peri-implantitis caused by foreign bodies. The treatment of choice was reverse torque removal of the dental implant. We highlight the need for shorter follow-up programs and periodic imaging examinations of patients with dental implants, which will permit to identify and manage the bone loss caused by inflammatory retrograde peri-implantitis in its early stages, increasing the success rate of implants and avoiding the need for explantation.