Quick Review for Patients
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Oral melanoacanthoma (melanoacanthosis) is a benign, focal melanosis of the oral mucosa characterized by dendritic melanocytes dispersed throughout the epithelium. It is a reactive lesion which appears to be unrelated to the melanoacanthoma of skin.
The lesion occurs almost exclusively in blacks and has a
female predilection. It is seen most frequently on the buccal
mucosa in 20-40 year-old persons, but can occur at any oral site and at any age.
Usually presenting as a single smooth, flat or slightly raised, dark brown to
black macule, the lesion often demonstrates an alarmingly rapid increase in size
and occasionally will reach a diameter of several centimeters within a period of
a few weeks. It is asymptomatic and not indurated, and bilateral examples have
Pathology and Differential Diagnosis
The pathognomonic feature of oral melanoacanthoma, sometimes the only obvious feature, is the occurrence of numerous brown dendritic melanocytes scattered throughout all layers of the epithelium, instead of being confined to the basal cell layer, as is the normal case (Figure 1). Basal layer melanocytes also are increased in numbers. Spongiosis and mild acanthosis are usually seen, as are occasional eosinophils and scattered subepithelial chronic inflammatory cells. The epithelial cells demonstrate no dysplasia.
Treatment and Prognosis
Incisional biopsy is recommended because of the
rapid rate of enlargement. Once the diagnosis has been established and it is
shown that there is no evidence of melanoma, no further treatment is
necessary. Occasionally the melanoacanthoma will undergo
spontaneous resolution following incisional biopsy; none have transformed into
References (Chronologic Order)
Note: For general references click on link to the left.
Goode RK, Crawford BE, Callihan MD, Neville BW. Oral melanoacanthoma. Oral Surg Oral Med Oral Pathol 1983; 56:622-628.
Wright JM. Intraoral melanoacanthoma: reactive melanocytic hyperplasia. Case report. J Periodontol 1988; 59:53-55.
Tomich CE, Zunt SL. Melanoacanthosis (melanoacanthoma) of the oral mucosa. J Dermatol Surg Oncol 1990; 16:231-236.
Heine BT, Drummond JF, Damm DD, Heine RD 2nd. Bilateral oral melanoacanthoma. Gen Dent 1996; 44:451-452.
Chandler K, et al. Melanoacanthoma: a rare cause of oral hyperpigmentation. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997; 84:492-494.
Seoane Leston JM, et al. Dark oral lesions: differential diagnosis with oral melanoma. Cutis 1998; 61:279-282.
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