Benign mole. Light micrograph of a section through a junctional benign melanocytic naevus (benign mole). The surface of the skin is across top. The melanocytic tissue is the rounded areas at right, located in the basal layers of the epidermis. Below this (across bottom) is the dermis. The stained areas (dark spots) are cell nuclei. Moles are caused by an abnormality or proliferation of melanocytes, the skin cells that produce the pigment melanin. Most moles are harmless but they can turn cancerous. For an intradermal naevus, see C006/5975.