Oral cancer ranks sixth among the malignancies in terms of worldwide prevalence, with more than 90% being pathologically squamous cell carcinoma (SCC) [1]. Oral SCC generally develops via multistep carcinogenesis. The squamous epithelium goes into irreversible change, including epithelial dysplasia and oral intra-epithelial neoplasia/carcinoma in-situ (OIN/CIS) [2], finally resulting in the development of invasive carcinoma through the accumulation of genetic abnormalities caused by persistent exposure to a carcinogen. Risk factors for oral SCCs are smoking, tobacco and betel quid chewing habits, and heavy alcohol consumption. In addition, chronic inflammation, including periodontitis, has been regarded as a possible risk factor for oral SCCs. Laprise et al. [3] conducted a case control study to estimate the extent to which high levels of periodontal disease were associated with oral cancer risk, using a comprehensive adjustment approach for confounding that involved a large set of life course variables. The authors concluded that their findings supported the hypothesis that high levels of periodontal disease increase the risk of oral cancer.

A recent report made a bold statement that dental implants also can be a cause of cancer by providing a “route of entry for squamous cell carcinoma” [4], and another report stated that dental implants can lead to SCC in at-risk patients [5]. The incidence of malignances associated with dental implants seems to be extremely low. Bhatavadekar [6] calculated the theoretical standardized incidence ratio (SIR) to be 0.0017 per million per year. However, recently, case reports of oral malignancies associated with dental implants have gradually been accumulating [7]. Raise et al. [8] pointed out that the number of such cases in the literature has increased sharply in the last decade.

In this study, we report a case of intra-epithelial neoplasia arising from peri-implant mucosa in a woman without a history of tobacco smoking or excessive alcohol consumption, and without predisposing factors for oral SCC, including leukoplakia, erythroplakia, or previous oral cancer.