新分類法(WHO 2005)に基づく日本人における歯原性腫瘍の臨床病理学的検討

The revised histopathological classification of odontogenic tumours by the World Health Organization (WHO) was published in 2005 in "Pathology and Genetics of the Head and Neck Tumours". This study sought to determine the relative frequency of odontogenic tumours in the Japanese population and to compare these data with previous classifications of odontogenic tumours.289 patients with odontogenic tumours diagnosed at the Department of Oral Pathology in Kyushu Dental College, Japan during a 20-year period from 1985 to 2004 were reviewed and reclassified according to the revised histopathological classification of odontogenic tumours by WHO published in 2005. Clinical data, including frequency, age, gender, and anatomical location, were also analyzed and collected.Odontogenic tumours accounted for 4.1% of all the oral and maxillofacial lesions (n=289).Of these, 289 patients (99.31%) had benign tumours and 2 (0.69%) had malignant tumours. The most frequent of the benign tumours were keratocystic odontogenic tumours (n=86), followed by ameloblastomas (n=81) and odontomas (n=79).These tumours constituted 84.43% of the all the odontogenic tumours. The mean age for benign odontogenic tumours was 32.36 ±19.83 years and for malignant tumours was 30 years, with the majority 189 (65.40%) of odontogenic tumours occurring in the second and the third molar region of the mandible, especially the posterior region 139 (48.10%). The male:female ratio for the all odontogenic tumours was 1:0.91.Conclusions:Keratocystic odontogenic tumours therefore tend to show a higher frequency of occurrence among odontogenic tumours than ameloblastoma, according to this new classification.