Malignant ameloblastoma: Real world outcomes of a rare odontogenic malignancy using the SEER database.

Abstract

e18148 Background: Ameloblastomas are rare odontogenic tumors and represent the second most common neoplasm of odontogenic origin. They predominantly arise in the jaw, most commonly the mandible, and occurrence outside the gnathic region is exceedingly rare. Although most ameloblastomas are benign, they are locally aggressive and, in rare instances, may undergo malignant transformation . Given the extreme rarity of this entity, population-level data describing its epidemiology and survival outcomes remain limited. This study evaluates incidence patterns, demographics, anatomic distribution, and overall survival of malignant ameloblastoma using the Surveillance, Epidemiology, and End Results (SEER) database. The goal of this study is to assist better in understanding of this lesser known and rare malignancy. Methods: A retrospective analysis was performed using the Surveillance, Epidemiology, and End Results (SEER) 17 registries from 2000 to 2022. We extracted histologically confirmed malignant ameloblastoma cases diagnosed between 0–90 years using the ICD code 9310/3. Variables analyzed included age, sex, race, primary site labelled. Overall survival was assessed using Kaplan–Meier estimates with log-rank testing using GraphPad Prism. Results: Among 171 patients, the median age at diagnosis was 48 years. The cohort included 111 males (64.9%) and 60 females (35.1%). Most patients were White (41.5%), followed by Black (28.6%), Hispanic (16.9%), Asian/Pacific Islander (11.7%), and American Indian/Alaska Native (0.5%); race was unknown in 0.5% of cases. Survival curves were compared based on gender, race and primary site of origin. The average months of survival based on gender and race showed no statistical significance. Mean overall survival (MoS) was calculated based on the involved organ system and compared across tumors originating in the mandible, bones of the skull, face and associated joints, retromolar area, gums, vertebral column, lung, overlapping bones, joints and articular cartilage, other bone sites, and unknown primary origin. The highest survival (270M) was seen with mandibular tumours and lowest survival with tumours originating in the bone (65M) (p value < 0.04). Conclusions: Malignant ameloblastoma is an exceptionally rare malignancy, accounting for a small fraction of odontogenic tumors. In this population-based analysis spanning over two decades only 171 cases were found. No significant differences in survival were observed based on sex or race. However, survival outcomes varied by anatomic site, with mandibular tumors demonstrating more favorable outcomes compared with non-gnathic bone involvement. Given the extremely low incidence of malignant ameloblastomas, larger studies are warranted to understand this rare malignancy. Acknowledgements: Editorial support and guidance were provided by Dr. Thirumaran.