RESUMEN
Aneurysmal bone cysts mostly occur in long bones and spine. It is relatively rare in the maxillofacial region. In this article, we present a 19-year- old woman with the complaint of swelling in the left mandibular premolar tooth. She had got antibiotic therapy after the diagnosis of dental cellulites. On the X-ray study, a well- defined unilocular bony lesion within the preapical premolar tooth was observed. The patient referred after six months with vast swelling in the left mandible associated with parestesia and rapid growth. In 3D CT study a multilocular lesion suggestive of vascular lesion was observed. Surgical resection was done with curettage and immediate reconstruction of the plate. Aneurysmal bone cyst is a non-neoplastic but locally aggressive tumor that due to its occasional rapid growth should be differentiated from other multilocular processes like amiloblastoma, ossifying fibroma, epithelial cyst and also giant cell granuloma and sarcomas. Treatment of choice is conservative surgical excision of the mass with curettage or enucleation