The majority of moles appear during the first two decades of a person's life. Acquired moles are a form of benign neoplasm, while congenital mole or nevi, are considered a minor malformation or hematoma and may be at a higher risk for melanoma.
The most common types of moles are skin tags, raised moles and flat moles. Benign moles are usually brown, tan, pink or black (especially on dark-colored skin). They are circular or oval and are usually small (commonly between 1–3 mm), though some can be large.
The cause is not clearly understood. Genes, Hormone changes during pregnancy and diabetics are associated. Dysplastic nevi and atypical mole syndrome are hereditary conditions (often 100 or more in number) higher risk of melanoma, a serious skin cancer. Other moles are junctional nevus, Compound nevus, Intra-dermal nevus, a classic mole or birthmark, blue nevus.
Clinical diagnosis can be made with the naked eye using the ABCD guideline (melanomas (a) Asymmetry, (b) a border that is uneven, ragged, or notched, (c) coloring of different shades of brown, black, or tan and (d) diameter that had changed in size.
If a melanocytic nevus is suspected of being a melanoma/skin cancer, it needs skin biopsy. Additionally, moles can be removed by laser, surgery or electrocautery.
In properly trained hands, some medical (CO2) lasers are used to remove flat moles level with the surface of the skin, as well as some raised moles. Other thinks lasers are not the best method for removing moles because the laser only cauterizes or, in certain cases, removes very superficial levels of skin. Moles tend to go deeper into the skin than non-invasive lasers can penetrate. A second concern about the laser treatment is that if the lesion is a melanoma, and was misdiagnosed as a benign mole, the procedure might delay diagnosis.