Abstract
Ewing Sarcoma is the second most common type of bone cancer in children. The dominant features of this malignant bone tumor are the tendency for rapid growth and metastasis. In addition, Ewing sarcoma of the mandible is extremely rare and can be mistaken for odontogenic infection. We report a 14-year-old girl who had had swelling, pain, and hypoesthesia in the left cheek for three weeks. She was diagnosed with pericoronitis initially, and then referred toour hospital due to worsening symptoms. CT and MRI revealed an expanding and destructive mass mainly in the left mandible. (18)F-fluorodeoxyglucose ((18)F-FDG) positron emission tomography (PET) and fused PET/CT demonstratedincreased uptake in the mandibular lesion. Whole-body (18)F-FDG PET images showed no abnormal activity except for the mandibular lesion. Histologic examination confirmed Ewing sarcoma. Although this tumor has an aggressive clinical behavior and rapid growth, early diagnosis can reduce patient's morbidity, mortality and thus it is important to distinguish it from periodontal inflammation.