Aneurysmal bone cyst of maxilla existing concurrently with a giant cell granuloma of mandible: a case report of an unusual presentation.

Aneurysmal bone cysts (ABCs) are relatively rare but well-described expansile, osteolytic psuedocysts are most commonly seen in the long bones, pelvis, and vertebra. Although a well-described lesion, much confusion exists in its pathogenesis especially of the associations of this lesion with other lesions. Approximately, one-third of patients with ABC present simultaneously with another bone pathology. The aim of this paper is to describe a rare case of simultaneously occurring ABC of the maxilla and mandible with the mandibular lesion occurring predominantly as a giant cell granuloma. The paper discusses the various histopathological variations of ABC as well as different lesions associated with ABC and tries to provide a review of different pathogenesis theories of this interesting lesion.