Question

Fallen fragment sign -

• A. Simple bone cyst
• B. Osteosarcoma
• C. Adamantinoma
• D. Aneurysmal bone cyst

Answer 1

The Correct Option is A

The "fallen fragment sign" is a radiological finding typically seen in a Simple bone cyst. This occurs when a fragment of bone, which is internally lined by the cyst, breaks off from the thin cortical lining and settles at the bottom of the cyst, creating the appearance of a fragment inside the cyst cavity on X-ray.

Let's break down the options to understand why the simple bone cyst is the correct answer:

• Simple bone cyst: These are fluid-filled cavities within bone, often in the metaphysis of long bones, and the fallen fragment sign is characteristic of these lesions.
• Osteosarcoma: This is a type of bone cancer, which typically presents with aggressive bone destruction and a "sunburst" pattern on X-ray, not the fallen fragment sign.
• Adamantinoma: A rare bone tumor that typically affects the tibia and presents as a mixed radiolucent and sclerotic lesion and does not display the fallen fragment sign.
• Aneurysmal bone cyst: These are blood-filled cystic lesions that cause bone expansion, often with a "soap bubble" appearance on imaging, and do not typically show a fallen fragment sign.

In summary, the correct association of the fallen fragment sign with a simple bone cyst helps in differentiating it from other bone pathologies.