The ossifying fibroma (OF), with the microscopic features of trabuclae or spherules of bone or cementum-like material in a cellular fibrous connective tissue stroma, is one of the most common benign fibro-osseous lesions in the jaw bones. The OF often occurs in patients from 20 to 40 years of age, which is a definite female predilection. The mandibles are involved far more often than the maxillas, especially the pre-molar and molar regions. It is slow-growing, bone producing, asymptomatic and well-demarcated. The OF is a disorder of odontogenesis or osteogenesis ascribed to bone marrow stroma cells (BMSCs) abnormality. However, the detailed mechanisms of OF’s oncogenesis, cytodifferentiation, and tumor progression remain unknown. In this article, we reported a huge central OF on the anterior mandible. The lesion was enucleated and peripheral ostectomy was done via intraoral approach and reconstructed with vascularized iliac block bone graft. After 25 months of follow up, the tumor had not recurred. This case shows that OF may be successfully treated by conservative surgical enucleation and peripheral ostectomy.

Ⅰ. Introduction
 Ⅱ. Case report
 Ⅲ. Discussion
 Ⅳ. Conclusion
 Ⅳ. Reference

• 문성용(Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University Dental Hospital) | Seong Yong Moon
• 김수관(Department of Oral and Maxillofacial Surgery, School of Dentistry, Chosun University Dental Hospital) | Su Gwan Kim
• 김학균(Department of Oral and Maxillofacial Surgery, School of Medicine, Chungnam National University Hospital) | Hak Kyun Kim
• 윤정훈(Department of Oral & Maxillofacial Pathology, College of Dentistry, Daejeon Dental Hospital, Wonkwang University) | Jung Hoon Yoon correspondence