
The haemorrhagicbone cyst (HBC) is an uncommon nonepithelial lined cavity of the jaws. The lesion is mainly diagnosed in young patients most frequently during the second decade of life. The majority of HBCs are located in the mandibular body between the canine and third molar region. Clinically, the lesion is usually asymptomatic in majority of cases and is often accidentally discovered on routine radiological findings as aunilocular radiolucent area with "scalloping effect". The definite diagnosis of haemorrhagiccyst is invariably achieved during surgery. Since material for histologic examination may be scant or non-existent, it is often very difficult for a definite histologic diagnosis to be achieved. In this article, we are reporting an unusual case of Haemorrhagic bone cysts involving the mandible, accidentally discovered during routine radiographic evaluation for orthodontic reason. The literature is briefly reviewed.