Oral melanoacanthoma (OM) is a benign acquired pigmentation of the oral mucosa that is seen almost exclusively in Black individuals, with a female predilection, and is most common in the third and fourth decades of life. While the pathogenesis of this lesion is not fully understood, OM is thought to be reactive in nature, arising in response to chronic trauma or chemical irritants.
OM presents as a well-demarcated, smooth macule or slightly elevated plaque with a relatively uniform dark brown to black color. Its size typically ranges from 0.5 to 3 cm in diameter. OM is most often solitary, but multifocal lesions have been reported. The buccal mucosa is the most common site of involvement. Occasionally, patients may develop a synchronous melanoacanthoma on the contralateral buccal mucosa. OM has also been reported on the lip, palate, and gingiva. Multifocal OM is most commonly seen on the palate. While OM is often asymptomatic, pruritus and/or pain may be present.
Patients who have been aware of the development of this lesion often describe a relatively rapid increase in size over a period of a few weeks. Spontaneous resolution has been reported if the inciting factor is withdrawn or after biopsy.
Oral melanoacanthoma - Oral Mucosal Lesion
Alerts and Notices
Synopsis
Codes
ICD10CM:
D10.30 – Benign neoplasm of unspecified part of mouth
SNOMEDCT:
394727000 – Melanoacanthoma
D10.30 – Benign neoplasm of unspecified part of mouth
SNOMEDCT:
394727000 – Melanoacanthoma
Look For
Subscription Required
Diagnostic Pearls
Subscription Required
Differential Diagnosis & Pitfalls
- Melanoma –This rare intraoral melanocytic malignancy usually develops on the hard palate or maxillary gingiva and typically enlarges as rapidly as a melanoacanthoma. Color variegation, ulceration, nodularity, and irregular borders are indicative of a melanoma.
- Melanocytic nevus – These slow-growing lesions are more commonly seen on the hard palate and gingiva.
- Amalgam tattoo – These are common lesions associated with embedded silver amalgam dental filling material within the soft tissue of the oral cavity. They are often found in or adjacent to areas where teeth have been restored.
- Smoker's melanosis – Occurs frequently in tobacco users and is characterized by brown macules found on the gingiva, although pigmentation on the palate and buccal mucosa can be appreciated. Pigmentation tends to resolve gradually after cessation of tobacco use.
- Blue nevus is usually less than 1 cm in size and evenly pigmented.
- Physiologic pigmentation – More than one macule is usually present.
- Drug-induced pigmentation may have a sudden onset and rapid progression but is widespread.
- Kaposi sarcoma (AIDS associated and non-AIDS associated) – May be violaceous or deep brown.
- Peutz-Jeghers syndrome (PJS) – Look for black to brown macules on the lip / oral mucosa as well as the presence of, or a history of, intestinal hamartomas.
Best Tests
Subscription Required
Management Pearls
Subscription Required
Therapy
Subscription Required
References
Subscription Required
Last Reviewed:10/07/2021
Last Updated:10/07/2021
Last Updated:10/07/2021
Oral melanoacanthoma - Oral Mucosal Lesion