RESUMO
AIM: To document a case of a keratocystic odontogenic tumour (KOT) involving the apical region in the maxilla mimicking a periapical lesion of endodontic origin. SUMMARY: Benign and malignant tumours, including odontogenic lesions, can be erroneously diagnosed as periapical radiolucencies. KOTs mimicking periapical lesions of endodontic origin are uncommon, especially when the lesions involve the maxilla. This article describes a 55-year-old man with a well-delimited, oval-shaped, radiolucent lesion, occupying the middle and apical third of teeth 22 and 23. After 30 days, the clinical and radiographic findings remained unchanged and the patient was referred for surgical removal of the lesion. Clinical, radiographic and histopathological features are also discussed and compared with current literature.