Brown-cyanotic nevus (dermal spot) is a kind of congenital non-genetic skin pigmentation disease, because it occurs in the zygomatic bone and is also called zygomatic mother spot, while the pigment is deposited in the dermis, which gives it the name of dermal spot. Zygomatic nevus (dermal spot) mostly occurs in women, and the age of onset is mostly from 16 to 40 years old, and some patients have family history. The main pathological feature is the symmetrical distribution of dark gray spots in the zygomatic area with a diameter of about 1~5 mm, without any conscious symptoms. Some patients with brown-cyanotic nevus (dermal spots) have a family history. Differential diagnosis: The disease needs to be distinguished from nevus of Ota and freckles. This disease was once thought to be a variant of nevus of Ota, but in fact it differs from nevus of Ota in both clinical features and histopathology, and some people call this disease acquired nevus of Ota or Hori’s spot. Nevus of Ota: Most of the lesions are unilaterally distributed and travel along the ophthalmic and superior frontal branches of the trigeminal nerve, with early onset, mostly at birth or at the age of 1 to 2. Freckles: The lesions are yellowish brown spots, relatively small, with early onset, mostly within 5 years of age, with obvious seasonality and aggravation in summer. Treatment: The earlier the zygomatic brown nevus (dermal spot) is treated, the better the effect. Because the younger the age, the better its absorption and the less pigment particles are deposited, the better the treatment effect. In addition, the area is small in the early stage, but becomes larger and the pigment color deepens in adults, which makes the treatment more difficult and increases the treatment cost. The Q-switched laser can achieve very satisfactory results in the treatment of zygomatic nevus with its powerful instantaneous power, highly concentrated laser energy and high pigment selectivity, breaking up pigment particles and discharging them through lymphatic tissues without affecting the surrounding normal tissues, thus achieving exact efficacy, no damage, no scar, little pain and no treatment cost. This results in precise efficacy, no damage, no scar, little pain and safe treatment. Because the pigment is burst in the dermis, it is unlikely to be burst at once or metabolized immediately. Therefore, Q-switched laser treatment for brown nevus usually requires about 3 treatments, with an interval of 3 months between each treatment, in order to allow the body’s phagocytes to completely metabolize and absorb the broken pigment particles and then eliminate them from the body.