A child presents with bilateral, painless expansion of the posterior mandible giving a 'cherubic' facial appearance with upward gaze of the eyes. Radiographs show multilocular radiolucencies in the posterior mandible. What is the most likely diagnosis?

Cherubism is a rare autosomal dominant condition caused by mutations in the SH3BP2 gene, characterized by bilateral fibrous replacement of the posterior mandible (and sometimes maxilla) beginning in early childhood (ages 2–5). The bilateral bony expansion produces the characteristic 'cherubic' facial appearance, and upward displacement of orbital contents causes the upturned 'heavenly gaze' appearance. Radiographically, it shows symmetric, bilateral multilocular radiolucencies in the posterior jaws. Cherubism typically stabilizes or regresses after puberty. Treatment for severe cases may include surgical remodeling.