Telangiectatic osteosarcoma(TAEOS) is a rare subtype of osteosarcoma(OS) composed of blood-filled or empty cystic architecture simulating aneurysmal bone cyst. TAEOSs account for 2-12% of all OSs. TAEOSs mostly develop around knee and proximal humerus, but TAEOSs of the jaws are rare. To the best of my knowledge, this is the fourth case of primary TAEOS affecting the jaws. A 36-year-old female who had been previously diagnosed osteosarcoma by biopsy reported with a chief complaint of throbbing and swelling of the right mandible. The patient received neoadjuvant chemotherapy followed by hemi-mandibulectomy. After surgery, patient received adjuvant chemotherapy. The patient is free of disease for 6 months after surgery. TAEOSs are mimicking other benign entities, such as aneurysmal bone cyst and central giant cell granuloma. Thus, careful diagnosis through thorough radiographic and histopathologic evaluation is important to establish a treatment plan, prognosis, prediction and management strategy.

Abstract
Ⅰ. INTRODUCTION
Ⅱ. CASE REPORT
Ⅲ. DISCUSSION
REFERENCES

• 이삭(서울대학교 치의학대학원 구강병리학교실) | Sak Lee (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea)
• 오규영(서울대학교 치의학대학원 구강병리학교실) | Kyu-Young Oh (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea)
• 윤혜정(서울대학교 치의학대학원 구강병리학교실) | Hye-Jung Yoon (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea)
• 조성대(서울대학교 치의학대학원 구강병리학교실) | Sung-Dae Cho (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea)
• 이재일(서울대학교 치의학대학원 구강병리학교실) | Jae-Il Lee (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea)
• 홍성두(서울대학교 치의학대학원 구강병리학교실) | Seong-Doo Hong (Department of Oral Pathology, School of Dentistry, Seoul National University, Seoul, Korea) Corresponding author