Atypical mole syndrome
Atypical mole syndrome is a disorder of the skin which is seen in approximately 2% of the population. It is defined when an individual has more than 50 moles composed of melanocytes (pigment producing skin cells) present on their skin, and three or more are atypical (unusual) in their appearance, such as their size, shape or colour. An atypical mole is one greater than 5 mm in diameter, often with flat and raised areas, oval rather than round, and with some colour variation.
Solitary atypical moles are individually benign moles with a low risk of progression to melanoma (a type of skin cancer). However, people with multiple atypical moles (atypical mole syndrome) are considered to have a higher risk (increased 7 to 10-fold) of developing melanoma compared to the general population, due to the presence of atypical moles especially if some of these moles are on the scalp, buttocks, or feet. The risk is increased further if one or more first or second degree relatives (i.e. a close blood relative including parents, full siblings or children, or a blood relative including grandparents, grandchildren, aunts, uncles, nephews, nieces or half-siblings, respectively) have been diagnosed with malignant melanoma; this combination is known as familial atypical mole syndrome.