Epidemiology and Clinicopathologic Features with Prognostic Implications of Conventional Ameloblastoma: A 22-Year Retrospective Study

Ameloblastoma is the most common odontogenic neoplasm of the jaws, characterized by locally aggressive behavior and high recurrence potential. Although its clinicopathologic features have been described in global populations, large-scale institutional data from the United States (U.S.) remain limited. This study aims to characterize the epidemiologic and clinicopathologic features of conventional ameloblastoma over a 22-year period and to identify factors associated with recurrence in cases submitted to a single U.S. academic surgical oral pathology laboratory. A retrospective review was conducted of 123 cases of conventional ameloblastoma submitted to the Surgical Oral Pathology Laboratory at the University of Iowa which receives specimens from various states in the U.S. Data included patient demographics, tumor site, radiographic findings, histologic subtypes, treatment modality, and follow-up information. Recurrence-free survival was analyzed using Kaplan-Meier and log-rank tests, and predictors of recurrence were evaluated by Cox proportional hazards modeling. Among the 123 cases, the mean age was 51 years (range: 11-93), and 56.9% were male. Most tumors involved the mandible (91.9%). Of the 90 cases with available radiographic findings, 54.4% were unilocular, 37.8% multilocular, and 7.8% mixed radiolucent–radiopaque. The most common histologic subtype was follicular admixed with other subtypes (61.8%). Among 39 patients with treatment data, 23 (59.0%) underwent resection, 11 (28.2%) had enucleation and curettage, and 5 (12.8%) received enucleation with peripheral ostectomy. Follow-up information was available for 35 patients, of whom 15 (42.9%) experienced recurrence within 8-360 months. Recurrence-free survival differed significantly by treatment modality (p = 0.006), with resection associated with markedly improved outcomes compared with more conservative treatments (adjusted p = 0.028). This study reinforces the importance of surgical treatment selection in the prognosis of conventional ameloblastoma and highlights the need for careful surgical planning to minimize recurrence. Additionally, mixed histopathologic subtypes within the tumor limited the prognostic value of histologic subclassification.