How are amalgam and graphite tattoos differentiated from oral malignant melanoma?

Updated: Jan 31, 2020
  • Author: Elizabeth Ann Bilodeau, DMD, MD, MSEd; Chief Editor: Jeff Burgess, DDS, MSD  more...
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The amalgam tattoo, as shown below, is a frequent finding in persons who have had dental amalgam restorations (ie, silver fillings in teeth). When the amalgam is removed with a high-speed dental handpiece, amalgam particles can be embedded or traumatically implanted in the oral mucosa. Silver from the amalgam leeches out of the embedded particles and stains (ie, tattoos) selected components of the fibrous connective tissue (eg, elastic, reticulin, oxytalan fibers) and highlights the blood vessels.

The pigment is often solitary, macular, gray-black, and found near where amalgams were placed and subsequently removed. The gingiva, palate, lateral tongue, and buccal mucosa are commonly involved sites. If the particle is large enough, a dental radiograph may show radiopaque amalgam particles in the soft tissue or bone. Fragments of the amalgam can be observed on histologic specimens, and, on occasion, a foreign body giant cell reaction is noted.

This image depicts two diffusely bordered, dark gr This image depicts two diffusely bordered, dark gray macules in the left posterior buccal mucosa adjacent to molar teeth that have been restored. The diagnosis is an amalgam tattoo.

Graphite tattoos result from pencil lead that is traumatically implanted, usually during the elementary school years. A gray-black pigmented, often macular area, commonly found in the palate, corresponds to the size of the implanted lead or the rub from its introduction. Older persons with these tattoos may not be able to recall the event.

Lead shot and bullets also leave "rub" tattoos in the soft tissue of people who experience such violence. Heavy metal ingestion, such as with lead, bismuth, or even the chemotherapeutic agent cisplatin, often creates linear pigmentation in areas of inflammation, referred to as Burton lines. Plaque bacteria provide sulfides for metallic salt deposition.

Although "asphalt" tattoos are less common on mucosal surfaces than on cutaneous surfaces, they are a source of pigmentation. These tattoos can occur occur in healed skin after bikers, runners, or the uncoordinated slide across paved surfaces ("road rash").

Intentional tattoos are readily identifiable. They are often words of emotion, vulgarities, letters, or symbols placed by the persons themselves or a tattoo artist. The tattoos are often deeply pigmented with a single color or a variety of colors. In some cases of self-mutilating behavior, the tattoos are blotchy, irregular, and alarming in appearance.

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