Background <p>Proliferative periostitis, also known as Garré osteomyelitis, is an uncommon periosteal reaction characterized by reactive bone formation secondary to chronic low-grade inflammation or infection, most often in pediatric patients.</p> Case Presentation <p>This image report describes a 6-year-old female who presented with a two-week history of right cheek swelling along the buccal aspect of tooth #30 and the lateral border of the mandible.</p> Diagnosis <p>Correlation of the clinical, radiographic, and histologic findings supported the diagnosis of proliferative periostitis.</p> Conclusion <p>Familiarity with radiographic and histologic findings help to ensure an accurate diagnosis.</p>