A mother brings her young son to the dental office. He has had bilateral jaw swelling developing progressively over several months. Radiographic examination shows bilateral multilocular radiolucencies of the jaw. What is the most likely diagnosis?

Cherubism is the classic diagnosis for bilateral jaw enlargement in a child with multilocular radiolucencies. It is an autosomal dominant condition (SH3BP2 mutation) that presents in early childhood with progressive, bilateral, symmetric enlargement of the mandible and sometimes the maxilla, giving the face a cherubic, full-cheeked appearance. Radiographically, bilateral multilocular radiolucencies resembling giant cell lesions are characteristic. The history of familial jaw enlargement in a young child is the defining presentation. Fibrous dysplasia typically causes unilateral ground-glass opacity, not bilateral multilocular lesions. Paget's disease affects older adults. Ectodermal dysplasia affects teeth, hair, and sweat glands but not jaw bone in this pattern.