Aneurysmal bone cyst of the zygomatic arch causing limited mouth opening

The Aneurysmal Bone Cyst (ABC) is an expansive osteolytic, radiolucent, multilocular, excentric, origin-dismissed lesion consisting of spaces filled with blood in any segment of the skeleton, being most frequently encountered in the diaphysis of the long bones or spinal cord. It may occur as distinct clinic-pathologic entity or as pathophysiologic alteration of a preexisting lesion, like giant-cells lesion, fibrous dysplasia, ossifying fibroma, osteoblastoma, epiphysary chondroblastoma and even malignant lesions as osteossarcoma. This paper reports a rare case of ABC in the zygomatic arch of a young female patient who presented facial asymmetry and progressive limitant mouth opening, treated by ressective surgical procedure and discusses the clinical, imaginological, histological and treatment features of this pathology.