Pathology · patient case question
What is the diagnosis for Patient A?
Patient case: Two unerupted teeth with pericoronal radiolucencies
Patient: Two patients
Chief Complaint: A: “My eye tooth never came down.” B: routine radiographic review.
Background: A, 16-year-old female: healthy, no symptoms. B, 42-year-old male: healthy, mild expansion of the posterior left mandible noticed by his hygienist.
Findings: A: an unerupted maxillary canine surrounded by a well-defined radiolucency that envelops the crown AND continues apically along the root, clearly PAST the cementoenamel junction. Faint flecks of radiopacity are visible within the lucency. B: an unerupted mandibular third molar within a lucency containing scattered calcifications of markedly varying size and density, some appearing ring-like.
Show answer and explanation
Correct answer: D. Adenomatoid odontogenic tumour
- A. This is the commonest MISdiagnosis for the lesion described, and separating the two is the entire point of the item. A dentigerous cyst attaches AT the cementoenamel junction and surrounds the CROWN ONLY. It does not extend apically along the root, and it does not contain calcified flecks.
- B. The calcifying odontogenic cyst is characterised histologically by GHOST CELLS, often shows more substantial calcification, and is frequently associated with an odontoma. It is a reasonable differential but the described features fit AOT.
- C. Ameloblastic fibroma is a mixed odontogenic tumour of young patients, but it is expansile and favours the POSTERIOR MANDIBLE.
- D. CORRECT. The ADENOMATOID ODONTOGENIC TUMOUR is remembered as the ‘two-thirds tumour’: two-thirds occur in FEMALES, two-thirds in the ANTERIOR MAXILLA, two-thirds are associated with an UNERUPTED TOOTH — most often the canine — and two-thirds occur in the second decade. The single radiographic discriminator from a dentigerous cyst is that the AOT radiolucency extends APICALLY PAST THE CEMENTOENAMEL JUNCTION, enveloping part of the root, and it typically contains faint snowflake flecks of calcification. It is encapsulated and benign, cured by simple ENUCLEATION, and it does not recur.
Note: This is the classic pairing from any radiographic atlas: for a pericoronal radiolucency, ask WHERE IT STOPS. Attached at the CEJ and around the crown only → dentigerous cyst. Extending beyond the CEJ down the root, with flecks, in the anterior maxilla of a teenage girl → AOT. A dentigerous cyst measuring under about 3 mm of follicular space is simply a normal follicle.