Cemento-ossifying fibroma (COF) is classified as a fibro-osseous lesion and usually presents as a progressively growing lesion that can reach a large size if left untreated. Fibrous dysplasia (FD) is a non-neoplastic development that affects the craniofacial bones and is characterized by painless hypertrophy due to the replacement of bone by abnormal fibrous tissue. Herein, a case of concurrent occurrence of COF and FD involving the right mandible is described in a 14-year-old male patient. In this review, the current knowledge of FD and COF is summarized, emphasizing the importance of integrating the understanding of clinical, radiographic, and histopathological features. In addition, the relevant aspects associated with differential diagnosis and patient care are evaluated.

Ⅰ. INTRODUCTION
Ⅱ. CASE REPORT
Ⅲ. DISCUSSION
    1. Radiological characteristics
    2. Histological characteristics
    3. Treatment
Ⅳ. CONCLUSION
    1. Availability of data and material
ACKNOWLEDGEMENTS
REFERENCES

• 박지송(서울대학교 치의학대학원 구강악안면외과학교실) | Ji Song Park (Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University)
• 명훈(서울대학교 치의학대학원 구강악안면외과학교실) | Hoon Myoung (Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University)
• 서미현(서울대학교 치의학대학원 구강악안면외과학교실, 서울대학교치과병원 원스톱협진센터) | Mi Hyun Seo (Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, Department of One-stop Specialty Center, Seoul National University Dental Hospital, Seoul, Korea) Corresponding author