Regression of a multilocular keratocystic odontogenic tumour without treatment

This report is of a 50-year-old woman with a large multilocular keratocystic odontogenic tumour that regressed after biopsy. At first visit, a swelling involving the right buccal region and right molar-to-retromolar region of the mandible was observed. Panoramic and posteroanterior X-ray examination showed a multilocular radiolucent lesion from the right premolar region to the ramus of the mandible causing resorption of the root of the right second premolar tooth. After a clinical diagnosis of ameloblastoma at the right mandible was made, intraoral tissue biopsy was performed. The histological diagnosis was keratocystic odontogenic tumour. However, the patient refused treatment and was lost to follow-up. When she returned to the department 8 years and 5 months later, the multilocular lesion had almost disappeared on panoramic and posteroanterior X-ray examination. Only a few small radiolucent lesions were present. The tissue sample obtained from one of the radiolucent lesions showed inflammation accompanying hyperplastic squamous cells. There were no features indicating odontogenic epithelium.