Odontomas: A clinicopathologic study in a Portuguese population

Objective: Odontoma is a tumorlike malformation (hamartoma) that contains odontogenic epithelium with odontogenic ectomesenchyme. Frequency and distribution of odontogenic tumor among a Portuguese population were analyzed and compared with previous reports. Method and Materials: A total of 65 odontogenic tumor cases were collected from the files of the Department of Pathology of Hospital São João, Porto, Portugal, and the Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), from January 1993 to December 2006. Of these cases, 48 were retrieved and analyzed. The final diagnosis of each case was based on the 2005 WHO histopathologic classification of odontogenic tumors, and to the authors' best knowledge, the present series represents the first study on odontomas in a northern Portuguese population. Results: Of the 65 odontogenic tumors cases, 64 (98.5%) were benign and 1 (1.5%), an ameloblastic carcinoma, was malignant. Odontoma was the most frequent odontogenic tumor (73.9%), followed by unicystic ameloblastoma (7.7%) and calcifying cystic odontogenic tumor (7.7%). Of the 48 odontomas (26 males and 22 females), 34 (70.8%) were compound and 14 (29.2%) were complex. Most odontomas (72.9%) occurred in patients under the age of 30, with a peak incidence in the second decade of life. Twenty-eight (58.3%) odontomas were in the maxilla and 20 (41.7%) in the mandible (P .05). Twentyeight (58.3%) of the 48 odontomas were associated with 33 impacted teeth, including 31 permanent teeth, 1 primary tooth, and 1 supernumerary tooth. The maxillary central incisor (n = 6; 19.4%) and the maxillary canine (n = 6; 19.4%) were most commonly associated with odontoma, followed by the mandibular canine (n = 5; 16.0%) and maxillary third molar (n = 4; 12.9%). Conclusion: This study provides clinical and pathological information on odotogenic tumors in a nothern Portuguese population. Keywords: odontoma, odontogenic tumor, Portuguese