Junctional nevi are usually flat and deeply pigmented. Intradermal nevi can be nonpigmented with a dome shaped appearance. By definition, congenital nevi are present at birth. They usually remain throughout life. Most congenital nevi are small but a small percentage are very large and are referred to as giant congenital nevi.
Controversy surrounds the risk of malignant transformation of congenital nevi.
These are ordinary appearing nevi that develop a depigmented halo around them. Occasionally the central nevus will regress. This is a blue black nodule with a smooth surface. The deep pigmentation is due to large amounts of melanin pigment within the deeper dermis. Dysplastic nevi Dysplastic nevi are moles that appear atypical both clinically and histologically.