Fluid-fluid level containing bone lesions
Fluid-fluid level containing bone lesions are best seen on MRI, although with narrow window width they can also be appreciated on CT.
Epidemiology
Their prevalence is estimated at ~3% of bone and soft tissue tumors 1.
Differential diagnosis
Their presence is non-specific, as they are seen in both benign and malignant lesions:
-
aneurysmal bone cyst (ABC)
- primary
- secondary to other underlying lesions such as
- simple bone cyst: especially after fracture
- telangiectatic osteosarcoma
- uncommon causes
- metastasis: especially from renal cell carcinoma (RCC) and lung cancer 3
- synovial sarcoma
- synovial hemangioma
- myositis ossificans
- adamantinoma 2
- neurogenic tumors 3
There is a mnemonic for fluid-fluid levels on MRI.