A flat, dark lesion is present on the buccal mucosa in the premolar region. No radiopaque particles are visible on the radiograph. What is the most likely diagnosis?

Correct answer: C. Melanotic macule

• A. Physiologic pigmentation is symmetric, bilateral, most often on attached gingiva, and present since childhood — not a solitary premolar-region lesion.
• B. Amalgam tattoo is a strong contender, and fine particles are frequently invisible radiographically. A history of a nearby restoration or extraction supports it; here the absence of radiopacity shifts the odds.
• C. Correct. A solitary, flat, well-circumscribed brown lesion with no radiographic particles is most consistent with a melanotic macule — a benign focal increase in melanin.
• D. Melanoma is rare in the mouth but must be considered for any pigmented lesion. Irregular borders, colour variation, growth or asymmetry make biopsy mandatory.

Note: ⚑ No key was marked in the recall for this item. The safe clinical rule matters more than the answer: a solitary pigmented lesion that cannot be confidently explained by a local cause should be biopsied.