Résumé : A tumor attached to the amelo-cemental junction of a third molar impacted in the maxillary tuberosity, consisted histologically of a myxomatous stroma, in which multicystic cavities lined by a columnar epithelium and mucoproducing cells, together with an aggressive squamous epithelial component were present. Although the diagnosis of polyp of the maxillary sinus cannot be excluded, this lesion most likely constitutes an unusual presentation for an odontogenic myxoma of the maxilla, in which an aggressive squamous epithelial component is present, along with a mucosecreting glandular component.