Simple Bone Cyst — MFDS Part 1 MCQ

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ModerateRadiologySimple Bone CystMFDS Part 1

A 17-year-old patient has an asymptomatic, well-defined unilocular radiolucency in the body of the mandible. The lesion scallops between the roots of adjacent vital teeth and causes little cortical expansion. Aspiration is non-productive apart from a small amount of serosanguineous fluid. What is the most likely diagnosis?

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Correct answer: E — Simple (solitary/traumatic) bone cyst

The diagnosis is a simple bone cyst, also termed a solitary or traumatic bone cyst. It typically occurs in young patients within the mandible and appears as a unilocular radiolucency that characteristically scallops between the roots of vital teeth, often with little expansion. The cavity lacks an epithelial lining and may be empty or contain scant straw-coloured or blood-stained fluid. A radicular cyst is associated with a non-vital tooth. A dentigerous cyst surrounds the crown of an unerupted tooth. Ameloblastoma more often produces expansion, root resorption or a multilocular appearance. An aneurysmal bone cyst is generally expansile, may be multilocular and typically yields a more substantial bloody aspirate.

Reference: Yucesoy MT et al. Radiographic and histopathologic characteristics of simple bone cysts: a retrospective study of 46 cases. BMC Oral Health. 2025. https://pubmed.ncbi.nlm.nih.gov/41402962/