BROWN MELANOTIC LESIONS
Ephelis and Oral Melanotic Macule
The common cutaneous freckle, or ephelis,represents an increase in melanin pigment synthesis by basal-layer melanocytes, without an increase in the number of melanocytes. On the skin, this increased melanogenesis can be attributed to actinic exposure. Ephelides can therefore be encountered on the vermilion border of the lips, with the lower lip being the favored site since it tends to receive more solar exposure than the upper lip (Figure 6-4).
Ephelis and Oral Melanotic Macule
The common cutaneous freckle, or ephelis,represents an increase in melanin pigment synthesis by basal-layer melanocytes, without an increase in the number of melanocytes. On the skin, this increased melanogenesis can be attributed to actinic exposure. Ephelides can therefore be encountered on the vermilion border of the lips, with the lower lip being the favored site since it tends to receive more solar exposure than the upper lip (Figure 6-4).
The lesion is macular and ranges from being quite small to over a centimeter in diameter. Some patients report a prior episode of trauma to the area. Lip ephelides are asymptomatic and occur equally in men and women. They are rarely seen in children.
The intraoral counterpart to the ephelis is the oral melanotic macule.These lesions are oval or irregular in outline, are brown or even black, and tend to occur on the gingiva, palate, and buccal mucosa. Once they reach a certain size, they do not tend to enlarge further (Figure 6-5). The differential diagnosis includes nevus, early superficial spreading melanomaamalgam tattoo, and focal ecchymosis. If such pigmented lesions are present after a 2-week period, hemosiderin pigment associated with ecchymosis can be ruled out, and a biopsy specimen should be obtained to secure a definitive diagnosis.
Microscopically, a normal epithelial layer is seen, and the basal cells contain numerous melanin pigment granules without proliferation of melanocytes. Melanin incontinence into the submucosa is commonly encountered. Rarely, melanin-containing dendritic cells are seen to extend high into a thickened spinous layer. Lesions of this nature are diagnosed as melanoacanthoma.
The oral melanotic macule is innocuous, does not represent a melanocytic proliferation, and does not predispose to melanoma. Once it is removed, no further surgery is required.