Pigmented nevi are a common problem in each of our skin, and many people actively request treatment for pigmented nevi because they are concerned about their malignancy. In fact, the malignant skin tumor most closely related to pigmented nevi is melanoma, which is the most malignant tumor in dermatology. We Chinese are more prone to malignant melanoma of the limb type, so it is best to have pigmented nevi on the hands and feet examined by a dermatologist and treated more aggressively. The malignant transformation of pigmented nevus into melanoma will have some external manifestations, such as the appearance of symptoms such as pain and itching, some break out and change in a short period of time. For some pigmented nevi that are easily irritated by friction, large in size, uneven in color and with unclear borders, it is also important to be alert. The diagnosis of melanoma needs to be confirmed by choosing skin pathology examination. Pigmented nevi are easily confused with some common skin malignancies, such as basal cell carcinoma and squamous cell carcinoma, which are misdiagnosed as pigmented nevi in the early stages of many people’s disease. Although the prognosis of these skin malignancies is relatively good, because they mostly occur in exposed areas such as the head and face, the late ulceration and erosion can cause serious disfigurement. Therefore, it is important to visit a dermatologist if you find a swelling or a strange discoloration on the skin later in life. So what is the best treatment for pigmented nevus? In the past, laser and freezing methods were often used to treat pigmented nevus, but it is believed that there are limitations of laser and freezing treatment for pigmented nevus: 1. Laser and cryotherapy are not easy to eradicate pigmented nevi, and it is troublesome to re-treat them after recurrence, and repeated stimulation of nest of nevus cells will significantly increase the chance of malignant transformation. It has been documented that many malignant melanomas are secondary to untreated pigmented nevi. Removal of pigmented nevi is today best done by surgical excision, especially for pigmented nevi over 1 mm in diameter. Surgery may seem complicated, but the advantages are obvious: 1. the tissue cut by surgery can be examined pathologically; 2. surgery is a radical treatment, and the chance of recurrence is small; 3. infection basically does not occur in regular surgery, plus the use of cosmetic stitches to reduce tension sutures, which can minimize the incidence of scarring. It should be emphasized here that the surgery (using cosmetic stitches with double reduction sutures) is not scar-free (this is very much related to the surgical site and the size of the lesion as well as the patient’s constitution), but the scar left behind should be minimal compared to laser, freezing or other invasive means. In summary, pigmented nevi under 1 mm can be treated with laser and high frequency electricity depending on the specific conditions, while the vast majority of pigmented nevi should be treated by surgery in dermatology and then the surgical skin pathology should be examined.