A radiograph confirms a discrete radiopacity in the gingiva above a maxillary lateral incisor with adjacent bluish-grey mucosal discoloration. What is the diagnosis?

Correct answer: B. Amalgam tattoo

• A. Physiologic pigmentation is symmetric, diffuse, brown, and bilateral — typically on the attached gingiva of patients with darker skin — and it is not radiopaque.
• B. CORRECT. AMALGAM TATTOO is the most common source of localized pigmentation in the oral mucosa. Metallic particles are implanted during restoration placement, extraction of a restored tooth, or endodontic surgery, producing a blue-grey-black macule that does NOT change over time. LARGER particles are RADIOPAQUE and visible on a radiograph — which is exactly the confirmatory finding described, and it makes biopsy unnecessary.
• C. Melanoma is a rare, expanding, irregular, often ulcerated lesion with asymmetry and color variation, and it demands immediate biopsy. It shows no radiopacity.
• D. A melanotic macule is a small, uniformly brown, flat lesion that is radiolucent and shows no radiographic finding.

Note: If the pigmented lesion is NOT radiopaque, has no plausible amalgam source, or is changing in size or color, biopsy it.