The scientific name of nevus is melanocytic nevus, also known as pigmented nevus, which is a benign swelling formed by the local aggregation of melanocytes and is found in almost everyone of all ages. The surface is smooth and can be hairy or hairless. The color can be tan, blue-black, black, or close to normal skin color. Generally, there are three types of nevi: junctional nevi, intradermal nevi and mixed nevi. Flat nevi suggest junctional nevi, slightly elevated ones are mostly mixed nevi, and hemispherical ones are intradermal nevi. How do I have to operate on a mole? Smaller and shallower moles (less than 3mm, flat) can be treated with laser (or radiofrequency electroacupuncture, etc.) because the trauma formed after laser cauterization is smaller and shallower, and the scar is not obvious after healing. The advantage is that it is less invasive, does not require sutures, and the recovery is often faster than surgery. However, the key to laser treatment is that it must be thorough, because repeated laser stimulation can cause malignant changes in residual mole cells, so it is not recommended to have more than 3 laser treatments on the same area. Larger and deeper moles (3mm or more, raised) need to be removed surgically. Because it is very unreliable to remove such a mole completely by the naked eye, experience, or even by hand. Most of them recur after a number of months or years. Even if the laser removes it at once, the formed trauma is large and deep, and after healing it is a flaky scar, which is very unattractive. Special attention If the mole changes in size, color, height, shape, or continues to itch and hurt, or even breaks down and bleeds in a short period of time, come to the hospital to have it surgically removed, and have a pathological examination done! Because this mole is very likely to have malignant changes. Case study Patient, female, right facial pigmented mole, recurred after one laser operation. Laser treatment is not recommended for this mole, and surgical excision should be preferred. The analysis is as follows: Diameter is greater than 3mm. Recurrence after laser surgery. Blue nevus (bluish nevus).