Dermatoscope image of a Reed nevus on the skin of a 7 year old Hispanic male patient, dermoscopy. This dark star-shaped mole is caused by an overactivity of melanocytes, the skin cells that produce the pigment melanin. It more common in children. Although a Reed naevus is benign (non-cancerous) they are often removed as they are difficult to differentiate from melanomas (skin cancers).