15 Pigmented lesions: Melanotic macule
Benign lesions similar microscopically to racial pigmentation, presenting normal or increased numbers of melanocytes often with subepithelial pigment-laden macrophages (melanophages), and not showing nevi cells thus helping differentiate them from melanocytic nevi, include:
- Melanotic macules, which consist of increased melanin, without increased numbers of melanocytes.
- Ephelides with sun exposure change in the amount of melanin and consequently color, but melanotic macules do not.
- Melanoacanthomas – rare acquired brown to black, usually single, benign areas of pigmentation of the mucosa, which can arise suddenly and enlarge, commonly seen on the buccal mucosa of women of African heritage. Besides increased amount of melanin in the basal layer they also typically show dendritic cells with melanin and eosinophils in the upper epithelium. They may be melanotic macules that appear suddenly as reactive lesions following trauma.
Definition: Melanotic macule is an acquired, small, flat, brown to brown-black, asymptomatic, benign lesion, unchanging in character. Prevalence (approximate): 1 in 1000 adults.
Age mainly affected: Adults.
Gender mainly affected: F > M.
Etiopathogenesis: The oral melanotic macule is a focal increase in melanin deposition. Labial melanotic macule (on the lip vermilion) is regarded as a distinct entity.
Melanotic macules are usually seen in isolation but may also be seen in:
- Peutz-Jeghers syndrome – an autosomal dominant trait related to serine/th/>