Primary and secondary ameloblastic carcinoma can be classified into not distinct categories but a single entity: A comparative study.

Background: Ameloblastic carcinoma (AC) was categorized into primary-type and secondary-type AC by 2005 World Health Organization (WHO) classification, whereas it is reclassified as a single entity in the new WHO classification. However, large sample studies are required to further evaluate and reinforce the classification.

Materials And Methods: The clinical behaviors and prognosis of primary AC (n = 25) and secondary AC (n = 24) were comparatively analyzed in a retrospective study of 49 AC patients with a mean follow-up period of 64.5 months.

Results: Differences in all the clinical parameters, including age, gender, tumor site, tumor diameter, teeth involved, maxillary sinus invasion, cranial base invasion, soft tissue invasion, treatment, metastasis, recurrence, and survival status, were not observed between primary and secondary AC groups (all P > 0.05). Cox regression analysis revealed that the association of all the parameters with patients' survival were not significantly different between the two groups, respectively. Consistently, Kaplan-Meier analysis showed that the significant differences in disease-free survival and overall survival were not also observed (P > 0.05).

Conclusion: We for the first time addressed that primary-type and secondary-type AC could be classified into not distinct categories but a single entity by a retrospective clinical study.