A bone cyst or geode is a cyst that forms in bone.
Types include:
Unicameral bone cyst
Aneurysmal bone cyst
Traumatic bone cyst
Diagnosis
On CT scans, bone cysts that have a radiodensity of 20 Hounsfield units (HU) or less, and are osteolytic, tend to be aneurysmal bone cysts.In contrast, intraosseous lipomas have a lower radiodensity of -40 to -60 HU.
Treatment and Prevention
Simple (Unicameral) Bone Cyst
Some unicameral bone cysts may spontaneously resolve without medical intervention. [Source: Wikipedia 
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