Jaw cysts and odontogenic tumours
- Oral pathology
Most dark areas in the jaw on X-ray are cysts from teeth. A few are tumours that grow, recur or, rarely, are malignant: all need a diagnosis.
What it is
Odontogenic cysts and tumours arise from the tissues that form teeth. The commonest cyst is the radicular (periapical) cyst at the root tip of a dead tooth. The dentigerous cyst surrounds the crown of an unerupted tooth, often a lower third molar or an upper canine. The odontogenic keratocyst is aggressive, recurs after removal and, when multiple, suggests Gorlin syndrome. Among tumours, the odontoma is a harmless mass of tooth tissue, and the ameloblastoma is a benign but locally invasive tumour of the posterior mandible that expands the jaw. Many lesions are found by chance on panoramic radiographs.
How to recognise it
- Radicular cyst: apex of a non-vital tooth; dentigerous cyst: crown of an unerupted tooth.
- Odontogenic keratocyst: high recurrence; multiple ones with basal cell carcinomas = Gorlin syndrome.
- Ameloblastoma: posterior mandible, multilocular «soap bubble» radiolucency, painless expansion.
- Warning signs: pain, numbness of the lip, loosening of teeth, rapid growth, ragged borders.
- Non-odontogenic lesions (giant cell lesions, metastases, myeloma, osteosarcoma) also occur in the jaws.
Differential and risks
- Lower lip numbness with a jaw lesion suggests malignancy or nerve compression and needs urgent assessment.
- A loose tooth without periodontal disease can be the sign of a destructive jaw lesion.
- Large cysts can cause pathological fracture of the mandible.
Next step / Initial management
- Incidental well-defined radiolucency: refer to the dentist or oral and maxillofacial surgeon for assessment, CBCT and biopsy as needed.
- Painful, growing, multilocular or ill-defined lesion, or numb lip: urgent referral to maxillofacial surgery.
- Multiple keratocysts: refer for genetic assessment (Gorlin syndrome) and skin surveillance.
Test yourself
Think of the answer, then tap the question to see it.
What is the most common odontogenic cyst?
The radicular (periapical) cyst at the root tip of a non-vital tooth.
Which cyst surrounds the crown of an unerupted tooth?
The dentigerous cyst.
What syndrome do multiple odontogenic keratocysts suggest?
Gorlin (naevoid basal cell carcinoma) syndrome.
Connections
Educational content; it does not replace assessment by a dentist or doctor and is not a clinical instruction. For facial or neck swelling with difficulty swallowing or breathing, a knocked-out tooth or bleeding that will not stop, go to an emergency department at once.
Sources: Odontogenic Cysts (StatPearls Publishing (NCBI Bookshelf), 2022); Odontogenic Tumors of the Jaws (StatPearls Publishing (NCBI Bookshelf), 2023); Dental Cone Beam Computed Tomography (StatPearls Publishing (NCBI Bookshelf), 2023).
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Representative model, for educational purposes only.