Ameloblastoma

Ameloblastoma is a rare, benign or cancerous tumor of odontogenic epithelium (ameloblasts, or outside portion, of the teeth during development) much more commonly appearing in the lower jaw than the upper jaw. It was recognized in 1827 by Cusack. This type of odontogenic neoplasm was designated as an adamantinoma in 1885 by the French physician Louis-Charles Malassez. It was finally renamed to the modern name ameloblastoma in 1930 by Ivey and Churchill.

While these tumors are rarely malignant or metastatic (that is, they rarely spread to other parts of the body), and progress slowly, the resulting lesions can cause severe abnormalities of the face and jaw leading to severe disfiguration. Additionally, as abnormal cell growth easily infiltrates and destroys surrounding bony tissues, wide surgical excision is required to treat this disorder. If an aggressive tumor is left untreated, it can obstruct the nasal and oral airways making it impossible to breathe without oropharyngeal intervention. The term "ameloblastoma" is from Old English amel 'enamel' and Greek blastos 'germ'.

Four types of ameloblastoma have been described by the WHO 2017 classification:

Previously known as solid/multicystic ameloblastoma. Usually presents with multiple large cystic areas.

Ameloblastoma with a single cyst cavity account for around 10% of ameloblastomas. Present in younger patients in their second and third decades of life, often in relation to unerupted third molar.

Histologically atypical ameloblastoma can, rarely, lead to metastasis, usually in the lung. 'Metastasis' look histologically identical to the primary tumour and are benign in nature.

The peripheral subtype composes 2% of all ameloblastomas.

Ameloblastomas can be found both in the maxilla and mandible. Although, 80% are situated in the mandible with the posterior ramus area being the most frequent site. The neoplasms are often associated with the presence of unerupted teeth, displacement of adjacent teeth and resorption of roots.