What does it mean if an abnormality is poorly-defined?

• A. Blending (abnormal trabeculae)
• B. Invasive (sparse trabeculae or enlarged marrow spaces)
• C. Punched-out
• D. Corticated (uniform)

Answer: (A)

Poorly-defined margins mean the abnormal area does not have a sharp edge where it ends. The best way to describe that appearance is blending of abnormal trabeculae with normal bone, so the abnormal pattern intermingles with the surrounding trabeculae and there’s no clear boundary. This tells you the process isn’t forming a discrete, well-demarcated lesion but rather merging into the surrounding bone structure. The other terms describe different border characteristics: a well-circumscribed, corticated area has a smooth, definite rim; a punched-out appearance shows sharp, round lucencies; and invasive describes bone destruction with sparse trabeculae or expanded marrow spaces—features that imply a more aggressive process rather than simple blending at the edge.