RESUMEN
Aggressive fibromatosis (AF) is an uncommon, benign, collagen-forming soft tissue neoplasm that is characterized by monoclonal myofibroblast cell proliferation and derived from musculoaponeurotic structures. It has a locally invasive pathological behavior and a high potential for recurrence. Fibromatoses with onset in infancy and childhood are characterized with higher cellularity and more aggressive growth. The mainstream management of AF is surgical removal with microscopically lesion-free margins. In advanced cases, radical surgery can lead to function loss and disfigurement. Hence, early diagnosis and management can avoid complications. Although uncommon (two to four cases per million per year are reported), approximately 25 percent of AF incidents occur in children younger than 15 years of age. Pediatric dentists are likely to be the first practitioners to encounter new cases of AF in younger populations and should have knowledge and understanding of this entity. The purpose of this report is to present a rare case of AF affecting the mandible of a young patient.