Pathology · patient case question
What is the MOST likely diagnosis?
Patient case: Incidental radiographic finding on a routine panoramic
Patient: Male, 26 years old
Chief Complaint: Attends for a routine check-up. No symptoms whatsoever.
Background: No relevant medical history. Has never had a panoramic radiograph before.
Current Findings: The panoramic shows tooth #17 retained and impacted against tooth #18. A well-defined unilocular radiolucency with a corticated border surrounds the crown of #17, attaching at the cementoenamel junction. There is no root resorption of adjacent teeth and no cortical expansion.
Show answer and explanation
Correct answer: B. Dentigerous (follicular) cyst
- A. A cementoblastoma is a RADIOPAQUE mass fused to a root, surrounded by a thin radiolucent rim, usually on a mandibular first molar and usually painful.
- B. CORRECT. A dentigerous cyst develops from the reduced enamel epithelium of an unerupted tooth. Its defining radiographic feature is a well-corticated unilocular radiolucency enveloping the CROWN and attaching at the CEMENTOENAMEL JUNCTION. Impacted third molars and maxillary canines are the classic sites. It is the second most common odontogenic cyst.
- C. A radicular cyst is INFLAMMATORY, arising at the apex of a NON-VITAL erupted tooth from the epithelial rests of Malassez. It is never associated with the crown of an impacted tooth.
- D. Periapical cemento-osseous dysplasia occurs at the apices of VITAL mandibular anterior teeth and evolves from radiolucent to mixed to radiopaque. It needs no treatment and is not pericoronal.
Note: ⚑ The differential that must always be voiced: a UNICYSTIC AMELOBLASTOMA is radiographically indistinguishable from a dentigerous cyst, and an ODONTOGENIC KERATOCYST can present the same way. Histopathological examination of the enucleated specimen is mandatory — the radiograph alone never makes this diagnosis.