Aneurysmal bone cysts have characteristics of a well-defined expansile osteolytic lesion, painful, usually affecting younger patients below 30 year old. The lesions develop normally around the knee, but also appear in other locations such as the proximal humerus or spine, but many other bones are also possible. In this case, the characteristics of the lesion are typical, but the location in the jaw is not a typical site. This patient was diagnosed early, however the treatment was delayed.

This case was kindly provided by Dr José Golin da Costa.