A radiolucency is noted at the apex of tooth #10 on a periapical radiograph, but the tooth is vital and asymptomatic. What is the most likely explanation?

Correct answer: A. The lateral fossa (canine fossa) — a normal anatomic depression in the maxilla

• A. Correct. The lateral fossa is a normal concavity in the maxilla superior to the lateral incisor apex. The thin bone there produces a diffuse radiolucency that mimics pathology. Vitality testing plus the diffuse, non-corticated border confirms it.
• B. A radicular cyst also requires pulpal necrosis and typically has a corticated border.
• C. A nasopalatine duct cyst is located in the midline between the central incisors, not at the lateral incisor apex.
• D. A granuloma requires a non-vital pulp; this tooth tests vital.