Pathology · patient case question
The tissue from the periapical lesion at tooth #7 shows a cyst lined by stratified squamous epithelium with a dense inflammatory infiltrate in the wall. What is the diagnosis?
Patient case: Deep caries on an upper premolar
Patient: Female, 36 years old
Chief Complaint: “Cold drinks hurt on my upper right, but it stops as soon as I swallow.”
Background: Healthy, no medications.
Findings: Tooth #4 has deep occlusal caries approaching the pulp with no radiographic periapical change; it responds sharply but briefly to cold and is not tender to percussion. Tooth #7 in the same patient is non-vital with a well-circumscribed periapical radiolucency; the excised soft tissue was submitted for histopathology.
Show answer and explanation
Correct answer: B. Radicular (periapical) cyst
- A. The lateral periodontal cyst has a thin lining with focal nodular thickenings of glycogen-rich clear cells, occurs lateral to a VITAL tooth, and lacks inflammation.
- B. CORRECT. A non-keratinised STRATIFIED SQUAMOUS lining of variable thickness, with arcading rete ridges and a fibrous wall heavily infiltrated by chronic inflammatory cells, on a NON-VITAL tooth, is the RADICULAR CYST — the most common odontogenic cyst. It arises when the cell rests of Malassez proliferate in response to pulpal necrosis. Cholesterol clefts and Rushton bodies may also appear.
- C. The dentigerous cyst has a thin, non-inflamed lining of two to four cells attached at the cementoenamel junction of an UNERUPTED tooth. The tooth here is erupted and non-vital.
- D. The odontogenic keratocyst has a thin, uniform PARAKERATINISED lining of six to eight cells with a palisaded, hyperchromatic basal layer and a corrugated surface — and characteristically a non-inflamed wall.