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Solitary Bone Cyst Diagnosis — MFDS Part 1 MCQ

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ModerateOral PathologySolitary Bone Cyst DiagnosisMFDS Part 1

An 18-year-old patient has an incidental, well-defined radiolucency in the posterior mandible. It has a scalloped superior margin extending between the roots of vital teeth. Which subsequent finding would establish the diagnosis of a solitary (simple) bone cyst?

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Correct answer: A — An empty or minimally fluid-filled cavity at exploration, with no epithelial lining in submitted tissue

The correct answer is A. A solitary bone cyst is a pseudocyst rather than a true epithelial-lined cyst. The characteristic radiographic pattern—scalloping between the roots of vital teeth—is suggestive, but definitive diagnosis is made by surgical exploration, which reveals an empty cavity or a small amount of serous or serosanguinous fluid. Any tissue obtained consists of scant fibrous tissue without an epithelial lining. Purulent aspirate indicates infection. CBCT appearances alone are not pathognomonic because other radiolucent jaw lesions may overlap. A palisaded epithelial lining would support an odontogenic keratocyst rather than a solitary bone cyst. Serum alkaline phosphatase is not a diagnostic test for this lesion. Exploration and curettage also induce bleeding and clot formation, commonly promoting osseous healing.

Reference: McLean AC, Vargas PA. Cystic Lesions of the Jaws: The Top 10 Differential Diagnoses to Ponder. Head and Neck Pathology. 2023;17(1):85-98. https://pubmed.ncbi.nlm.nih.gov/36928736/