Case report: an unusual finding of a solitary bone cyst in a patient with a fractured mandible

The World Health Organization classification of odontogenic tumours (1992) categorizes the solitary bone cyst (SBC) as a ‘non-neoplastic bone lesion’. The cyst is known by several alternative names, including simple bone cyst, traumatic bone cyst, unicameral bone cyst, progressive bone cavity, extravasation cyst, and haemorrhagic bone cyst.1^,2^,3 It is relatively uncommon, with a reported incidence of 0.6% (from a study of 3353 bone cysts)2 and tends to occur more frequently in males, presenting in the second and third decades.

A 16-year-old male presented at the hospital A&E Department following an alleged assault. The patient was diagnosed clinically with a fractured mandible, as he presented with malocclusion and a mobile fracture site between the lower right first molar and second premolar teeth. Appropriate radiographs were taken which revealed a right subcondylar fracture of the mandible. In addition, a pathological fracture of the right body of the mandible in association with a well circumscribed, unilocular cystic area present in the lower right second premolar to lower right second molar region was identified (Figure 1). The presence of the cyst was unknown to the patient; he had been completely asymptomatic.