A teenager presents with painless, symmetrical bilateral expansion of the posterior jaws giving a 'cherubic' appearance. The most likely diagnosis is:

Correct answer: B. Cherubism

• A. Fibrous dysplasia is typically unilateral and monostotic in the jaws.
• B. Correct. Bilateral, symmetric jaw expansion in a child/teenager is characteristic of cherubism.
• C. Paget disease affects older adults.
• D. Osteopetrosis causes dense bone, not bilateral cystic expansion.