Ameloblastomas are the most common benign neoplasm of odontogenic nature. Desmoplastic ameloblastoma (DA) was included in the World Health Organization Classification of Head and Neck Tumors (WHO-2005) as a variant of ameloblastoma with specific clinical, image, and histological features. This case report focuses on a DA which occurred in the mandible of a 25 year-old man. The main signals and symptoms included painless swelling with buccal expansion and tooth displacement. Panoramic and periapical radiographs and cone-bean computed to- mography demonstrated an image mimicking a benign fibro-osseous lesion. The lower border of the mandible was not involved, but tooth displacement could be observed. An incisional biopsy was performed, and the DA was diag- nosed. A marginal resection, maintaining the lower border of the mandible, was performed on teeth 46 to 31. The post-operative period was uneventful. The patient is undergoing routine follow-up and is currently free of disease.