On a periapical radiograph, a lateral incisor has caries extending to the pulp and a periapical radiolucency. What is the most likely diagnosis for the radiolucency?

Correct answer: B. Radicular cyst (apical cyst)

• A. ❌ Globulomaxillary cyst classically appears between the upper lateral incisor and canine as a pear-shaped radiolucency in a VITAL tooth — the tooth-related pulp involvement here makes radicular cyst more likely.
• B. ✅ Correct. A periapical radiolucency at the apex of a tooth with pulp involvement (caries to pulp, necrosis) is most likely a RADICULAR CYST or periapical granuloma — arising from epithelial rests of Malassez stimulated by pulpal infection. This is the most common periapical pathology.
• C. ❌ Nasopalatine duct cyst is located at the midpalate/incisive foramen — not at the periapex of a lateral incisor.
• D. ❌ Lateral periodontal cyst is lateral to root surfaces in vital teeth — not at the apex of a carious tooth.