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 ]