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Case contributed by Melbourne Uni Radiology Masters


Jaw pain.

Patient Data

Age: 56-year-old
Gender: Male

Panoramic radiograph


Lytic lesion seen in the mandible which could be a KCOT or an ameloblastoma. 

CT Mandible


There is an expansile lytic lesion involving the left mandible, measured at approximately 34 x 16 x 32 mm. There is cortical destruction at the buccal surface. 37 and 38 are both absent. The lesion extends to the left mandibular canal. Artefacts from filling of 36 noted. Soft tissue component of the tumor is seen together with gas. The outer cortical margin of the left hemimandible is preserved. The upper aspect of the left mandibular ramus is intact. No other focal bony destructive lesion identified within the mandible. No significant abnormality is seen within the TM joints. Minimal mucosal thickening is seen in the right maxillary sinus base. Several  lymph nodes are evident within the neck, without significant lymphadenopathy.


There is a focal bony expansile destructive lesion in the left hemimandible in keeping with aameloblastoma or a KCOT.

Case Discussion



Sections show fibroadipose tissue with two lymph nodes. One lymph node contains a 12mm maximum dimension well demarcated tumor comprising nests and anastomosing islands of columnar cells within a fibrotic stroma. There is peripheral palisading of columnar cells with subnuclear vacuoles and reverse nuclear polarity. The center of the nests contain stellate reticulum-like cells with frequent cyst formation. Significant nuclear atypia, mitoses and necrosis are not seen. Perineural invasion is not identified. The tumor is 0.9mm from the resection margin. The remaining lymph node is unremarkable.

DIAGNOSIS: Left soft tissue ameloblastoma: Metastatic ameloblastoma within 1 of 2 lymph nodes; resection margins clear of tumor.


Ameloblastomas, previously known as an adamantinoma of the jaw, are benign, locally aggressive tumors that arise from the mandible, or less commonly from the maxilla. Usually presented as a hard painless lesion near the angle of the mandible in the 3rd to 5th decades of life. 

On imaging, they are commonly identified as a well-defined, expansive, and multiloculated ("soap bubble") lesion in the posterior mandible.

General imaging differential considerations include:

  • dentigerous cyst: the relationship between ameloblastomas and dentigerous cysts is a controversial one, 20% of ameloblastomas thought to arise from pre-existing dentigerous cysts
  • odontogenic keratocyst (OKC): usually unilocular with thin poorly enhancing walls
  • odontogenic myxoma: can be almost indistinguishable
  • aneurysmal bone cyst (ABC)
  • fibrous dysplasia

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