Aneurysmal bone cyst of the mandible

This paper described a case of aneurysmal bone cyst, one of extremely rare nonodontogenic diseases occurring in the jaws. An asymptomatic cystic lesion developed in the lower jaw was noted accidentally in a 14-year-old boy by routine dental X-ray examination and the patient was referred to our clinic for further detailed examination. Although slight bony expansion was palpated on the buccal side of the right premolar region, the overlying mucosa did not show any pathologic changes with healthy teeth in the corresponding region. No swelling of lymph node was observed in the affected region. Panoramic roentogenography revealed a monocystic radiolucent shadow at 543 apex portion, suggesting a presence of bone trabeculae. The margin of the shadow was clear as a whole except for slightly unclear proximal medial portion. A puncture using 20 G needle was performed from 4 apex portion which required intensive compression. Fresh red blood could be aspirated without any resistance. Aneurysmal bone cyst was strongly suggested by clinical and roentographic findings in addition to the result of puncture test.A surgical treatment was performed considering the possibilities of recurrence, massive hemorrhage, deformity of the jaw and abnormal occlusion. After intermaxillary fixation, a serial resection of mandible was carried out extraorally including the lesion. After the affected site was completely removed by curettage, the resected bone was returned to the original site and sutured. Clips obtained from the iliac bone was sampled and grafted in the bone defect site. The operation was completed without any abnormal occlusion or deformity of the jaw. No epithelial lying was observed in the tissue removed by operation, and the histopathological finding confirmed the clinical diagnosis.Except for sensory paralysis noted in the right submental region, there was no other anomalies. A case of aneurysmal bone cyst was reported in this paper, emphasizing the importance of puncture examination in the clinical diagnosis as well as the surgical procedure for avoiding abnormal occlusion and deformity of the jaws.