Oral medicine:16. radiolucencies and radio-opacities. c. odontogenic tumours

Specialist referral may be indicated if the Practitioner feels:

Odontogenic tumours are rare, are often asymptomatic, and discovered incidentally on imaging (Table 1). They are generally slow-growing and may reach a large size before becoming symptomatic, eg:

They usually appear as well-defined corticated unilocular or multilocular radiolucencies but, unlike cysts, they are more likely to cause root resorption and buccal and lingual cortical expansion.

The majority of odontogenic tumours are benign. Management is surgical and is dependent upon the type of tumour and varies from enucleation to resection.

Benign odontogenic tumours are 100 times more common than malignant ones: most (>50%) are odontomas, or ameloblastomas (around 10%).

Ameloblastomas are significant since they may recur or metastasize. Composed of ameloblast-like epithelial cells arranged as a peripheral layer around a central area resembling stellate reticulum, two main histological types exist. The follicular type contains discrete islands (follicles) of epithelial cells: the plexiform type consists of anastomosing strands. Ameloblastomas predominate in the posterior mandible, presenting typically in third to fifth decades as a slow-growing, painless, uni-or multi-locular mass (‘soap-bubble’ appearance on imaging) (Figures 1 and 2) usually replacing a tooth and producing more buccolingual expansion and knife edge root resorption than does KCOT (but differentiation is difficult by plain radiography or CT). MRI may then help.