The ameloblastoma is an uncommon benign but locally aggressive odontogenic tumour. First recognised in 1827 ameloblastoma is thought to account of between 13-58% of odontogenic tumours and may arise from the remnants of tooth-forming components or the basal epithelial cells of the oral mucosa.  The 2005 World Health Organization (WHO) classification of odontogenic tumours described 4 categories of ameloblastoma; solid/multicystic; unicystic; peripheral or desmoplastic. Surgery is the first choice of treatment.

The aim of this review was to evaluate the global incidence of ameloblastoma.

Methods

Searches were conducted in the PubMed, Embase, Scopus and Web of Science databases. Only English language studies were considered. Three reviewers independently selected and assessed study quality. A meta‐analysis was conducted and a pooled incidence rate presented expressed per 1,000,000 population.

Results

• 49 studies were included.
• 42 studies provided data on 6446 ameloblastoma from 27 countries.
• 53.2% were male and 46.7% female (ratio 1.14:1).
• 28 studies provided age data the peak incidence being in the 3^rd decade.
• 87.2% of ameloblastoma were located in the mandible.
• 29 studies included data on tumour type, 67.7% were solid/multicystic; 26.2% unicystic; 3.6% peripheral and 1% peripheral.
• 21 studies presented histology data, follicular (24.8%) and the plexiform patterns (24.7%) were the two most common patterns, acanthomatous (5.7%), granular cell (2.5%), and basal cell (0.4%) patterns were rare.
• 7 studies from 6 countries (Australia, Netherlands, Nigeria, South Africa, Sweden, Tanzania) were included in a meta-analysis of incidence rates.
  • The pooled incidence rate of ameloblastoma was 0.92 per 1,000,000 person‐years (95%CI;0.57–1.49), with significant heterogeneity I² = 98.64%.

Conclusions

The authors concluded: –

The pooled incidence rate was determined to be 0.92 per million person‐years, confirming that ameloblastoma is a rare odontogenic tumour. We saw a slight male preference (53%) and the peak age incidence in the third decade of life. The mandible is the preferred site. The most common type of ameloblastoma is solid/multicystic, and the most histopathologic patterns are follicular and plexiform. The recent uniform classification such as 2005 WHO classification of odontogenic tumours should be a reference for histological diagnosis of ameloblastoma. More epidemiological studies on the incidence rate of ameloblastoma are needed, especially in Asia and America, to determine the global incidence of ameloblastoma more accurately.

Comments

This review has searched a broad range of databases but restricting the inclusion criteria to English language publication means that some relevant publications may have been missed. While data was reported from 27 countries only Europe, Africa and Australia are represented in the incident rate meta-analysis. There is a lack of detail provided in relation to inclusion and exclusion criteria and the study quality assessment although a process is described.

Although this review provides a useful update on ameloblastoma incidence the lack of detail provided in the review, the potential to have missed relevant studies and the small number of studies that have contributed to the pooled incidence rate calculation need to be taken into consideration when considering the findings.

Links

Primary Paper

Hendra FN, Van Cann EM, Helder MN, Ruslin M, de Visscher JG, Forouzanfar T, deVet HCW. Global incidence and profile of ameloblastoma: A systematic review and meta-analysis. Oral Dis. 2019 Jan 6. doi: 10.1111/odi.13031. [Epub ahead of print] Review. PubMed PMID: 30614154.

Picture Credits

By Nephron – Own work, CC BY-SA 3.0,