Aneurysmal Bone Cyst vs. Simple (Traumatic) Bone Cyst — which feature is characteristic of the Simple Bone Cyst?

Correct answer: A. Scalloping around tooth roots without true cystic lining, non-expansile, mandibular predominance

• A. Correct. The simple (traumatic) bone cyst is intraosseous without a true cystic epithelial lining, mandibular-predominant, well-defined/radiolucent, and characteristically scallops between roots without displacing them, generally non-expansile and asymptomatic; treatment is curettage to initiate bleeding and bony fill.
• B. This 'ballooned,' expansile, blood-filled pseudocyst description is characteristic of an aneurysmal bone cyst, not the simple bone cyst.
• C. Neither lesion is classically described as 'bilateral with a true epithelial lining' — distractor combining unrelated features.
• D. Significant tooth displacement is more characteristic of the aneurysmal bone cyst (expansile) than the simple bone cyst (non-expansile).

Note: Study both cysts carefully — one may be presented as a description and the other as a clinical case.