Benign mole. Light micrograph of a section through an intradermal benign melanocytic naevus (benign mole). The surface of the skin is across top. The melanocytic tissue is filling the upper dermis, the large area across centre and bottom, below the upper skin layers. Notably, the melanocytic tissue is not present in the basal layers of the epidermis. 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 a junctional naevus, see C006/6060.