RESUMO
Leukoplakia, a common lesion in the oral cavity, is considered a premalignant lesion that can develop into carcinoma. In 1986, a group of pathologists described a variant of epithelial dysplasia and named it "koilocytic dysplasia" (KD). This article presents a case of KD that was identified for 12 years as "carcinoma in situ". Even after removal of the lesion, it recurred with no signs of malignancy. The histopathological findings revealed all of the signs of KD (koilocytosis, acanthosis, multinucleated keratinocytes and atypical mitoses). Liquid-based cytology and hybrid capture were performed to confirm the diagnosis. Despite a professional recommendation to have the lesion removed surgically, the patient chose periodic clinical control. The mechanism of HPV transmission in the oral cavity still remains partially unknown. Additional studies on this subject are required to better understand the role of HPV in cell transformation in the oral cavity.