Which conditions are included in the differential diagnoses of head and neck mucosal melanomas?

Updated: May 07, 2020
  • Author: Neeraj N Mathur, MBBS, MS, DNB(ENT), MNAMS, FAMS; Chief Editor: Arlen D Meyers, MD, MBA  more...
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The differential diagnosis for intraoral melanotic lesions include mucosal melanoma, amalgam tattoos (focal argyrosis), melanotic macule, oral mucosal nevi, and melanoacanthoma.

Amalgam tattoos are blue-black discolorations of the oral mucosa secondary to the deposition of amalgam during restorative or surgical procedures, and they are the most common reason for mucosal pigmentation in the oral cavity. Amalgam tattoos are twice as common as melanotic macules and 10 times more common than oral nevi.

Melanotic macules are benign, pigmented lesions that do not appear to have malignant potential and are most commonly found on the vermilion border.

Oral nevi are relatively rare, with a prevalence of 0.1%. These lesions are more common in females (female-to-male ratio, 2:1) and black individuals. Although definitive transformation to melanoma has not been documented, oral nevi may represent precursor lesions.

Melanoacanthoma is a lesion thought to be a reactive process and is not related to melanoma formation. However, it may mimic melanoma because of its rapid increase in size in a few weeks.

Pigmentation of the oral mucosa may also occur secondary to an inflammatory reaction to heavy metals or tobacco. Drugs commonly associated with mucosal pigmentation include antimalarials, estrogen, clofazimine, 5-fluorouracil, ketoconazole, busulfan, azidothymidine, doxorubicin, and minocycline.

For more information, see Pathology of Benign Melanocytic Nevi and Pathology of Dysplastic (Atypical) Melanocytic Nevi.

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