Pathology · single question
Histopathology of a biopsy from a periapical lesion shows fibrous connective tissue with a lining of stratified squamous epithelium. What is the MOST likely diagnosis?
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Correct answer: D. Periapical cyst
A periapical (radicular) cyst is defined histologically by a cystic cavity lined with non-keratinizing stratified squamous epithelium (derived from rests of Malassez) surrounded by fibrous connective tissue with chronic inflammatory cells. This is the key differentiator: a granuloma has NO epithelial lining; an abscess has acute inflammatory cells and no lining; a dentigerous cyst is associated with an unerupted tooth crown.
- A. ❌ A periapical abscess contains acute inflammatory cells (neutrophils), necrotic debris — no epithelial lining.
- B. ❌ A dentigerous cyst is associated with the crown of an unerupted tooth and has a thin, non-keratinized lining — but is not related to the periapex of an erupted tooth.
- C. ❌ A periapical granuloma contains granulation tissue with chronic inflammatory infiltrate but NO epithelial lining.
- D. ✅ CORRECT – A periapical cyst shows fibrous connective tissue wall lined by stratified squamous epithelium (rests of Malassez).