Features
These lesions are small (usually 2-3mm in diameter) and have a uniformly brown colour although some become slightly lighter towards the margins. As they mature during adolescence, they darken and become more raised. It is important to note that this change does not indicate a malignant transformation if it occurs in isolation. This risk is increased when there are large numbers of atypical lesions or a positive family history of malignant melanoma. It follows, therefore, that any suspicious changes (as discussed in the section on malignant melanoma) should not be ignored.
Incidence
Almost universal.
Aetiology
Benign proliferation of melanocytes of unknown cause.
Differential Diagnosis
Atypical mole. Malignant melanoma. Pigmented basal cell carcinoma.
Treatment
None required. If unsure of the diagnosis, excision biopsy may be indicated.