Aneurysmal bone cyst

Case contributed by Lee-Anne Slater
Diagnosis certain


Painful proximal tibia following minimal trauma.

Patient Data

Age: 6 years
Gender: Male

Note: This case has been tagged as "legacy" as it no longer meets image preparation and/or other case publication guidelines.

Right leg


Tibia and fibula x-ray demonstrates an expansile lucent lesion in the proximal tibia with evidence of a pathological fracture.

MRI knee


Axial T2 MRI images show multiple fluid-fluid levels within the expansile bone lesion in the proximal tibia. Coronal T1 imaging shows the lesion to have low T1 Signal with the septations only just visible. Post-contrast T1 imaging demonstrates enhancement of the septa which can be seen in aneurysmal bone cysts.

Case Discussion

X-ray of the tibia and fibula show an eccentric lucent bone lesion with evidence of a healing pathological fracture, and MRI confirms that this lesion is an aneurysmal bone cyst with multiple fluid-fluid levels seen on the T2 imaging.

Enhancement of the septa are seen in this case and can be seen with aneurysmal bone cysts. There is however never any enhancement of the cystic components.

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