A radiolucency needs an explanation
A well-defined jaw radiolucency can suggest a cyst, but its outline alone does not establish which lesion is present. Begin with the site, relationship to teeth, vitality findings and the full radiographic pattern. Then consider whether tissue examination supports the proposed diagnosis.
Radicular cyst
A radicular cyst is inflammatory and is associated with a non-vital tooth. Its relationship to the involved tooth is therefore diagnostically relevant. University teaching cases also demonstrate that a lesion near a root apex may prove to be something else when vitality and histology do not fit. [1]
Dentigerous cyst
A dentigerous cyst is a developmental cyst associated with the crown of an unerupted tooth, typically with attachment near the cemento-enamel junction. This relationship helps frame the differential diagnosis but should be assessed with the rest of the case. [2]
Odontogenic keratocyst
Odontogenic keratocysts occur in the jaws and can recur after treatment. Recognising the diagnosis therefore has implications for the surgical discussion and follow-up. [3] A pericoronal location should not automatically be accepted as sufficient proof of a dentigerous cyst.
Put the findings into the requisition
For a useful submission, record the affected tooth or teeth, vitality where relevant, the provisional diagnosis, prior treatment and available imaging. Explain whether the material was an incisional sample or an enucleated lesion.
Ask whether the microscopic conclusion adequately explains the clinical and radiographic findings. If the tissue is extensively inflamed or the sample is limited, discuss any interpretive uncertainty with the pathologist.
Teach the reasoning
For students, a useful exercise is to write one sentence explaining why each diagnosis is being considered and another identifying the finding that would make it less likely. This develops diagnostic reasoning beyond memorising a radiographic shape.
The final diagnosis should be supported by the available evidence and expressed with the confidence that evidence permits. Follow-up should be tailored to the established lesion and the treating team’s assessment.
References
[1] University of Washington School of Dentistry. Case of the Month, August 2011 diagnosis. Read source
[2] University of Washington School of Dentistry. Case of the Month, August 2008 diagnosis. Read source
[3] Leeds Teaching Hospitals NHS Trust. Treatment of Odontogenic Keratocysts. Read source