Nevus are localized skin pigment abnormalities, which can occur at birth or the day after tomorrow. Healthy people can usually find 15 ~ 20 moles on the skin. Most of these moles are benign and do not need treatment. But there are some moles on the face, which affect the appearance and can be removed in different ways. There are several commonly used methods to remove moles: laser method, freezing method, electrocautery method, spot scanning method and chemical agent method.

Black spot nevus is a kind of pigmented nevus, which often attracts special attention because of its local blackening, rough skin and long hard and short hair. Attention should be paid to moles that occur in parts of the body that are vulnerable to friction or injury, such as rapid growth and increase of the body, fading or deepening of the color, shedding of short hairs on the mole, redness around the mole, faintly visible bloodshot, festering and scabbing on the surface, and even forming lasting ulcers. Nearby lymph node enlargement, or some small satellite-like nevus around the big nevus, all indicate that the nevus has a tendency to malignant transformation. You should go to the hospital to ask a dermatologist and a surgeon for diagnosis, so as to deal with it in time. For the treatment of black spot nevus, small nevus with a diameter less than 0.5 cm can be cauterized by laser or high frequency electrotome. Its advantages are simple operation, less damage to normal tissues and less scar after healing. The disadvantage is that it is difficult to take the nevus tissue for pathological examination and it is not easy to remove it. There are also freezing and chemical etching to remove moles, because the impurities left behind stimulate the malignant transformation of nevus cells, which is not suitable. Resection of pigmented nevus by trephine can make up for the above shortcomings. After local skin anesthesia, the whole pigmented nevus is drilled with a trephine 0.2 cm larger than the diameter of the nevus, and the incision can be sutured with fine thread. Because the long axis of the incision is consistent with the skin lines or expression lines, the postoperative scar is not obvious and the cosmetic effect is good.

What kind of mole should be removed?

Dr. Li pointed out that in addition to aesthetic factors, in order to avoid becoming malignant melanoma, the following kinds of moles should be removed:

1. moles that will be stimulated by long-term friction, such as those on bras and waist.

2. Nevus with atypical changes. Nevus with atypical appearance may become malignant, such as very dark nevus, uneven (mottled) pigment, uneven or irregular edge, unclear boundary, asymmetric left and right, and statistically larger than 5 mm in diameter.

3. A mole will change suddenly and rapidly. If the mole of the whole body changes at the same time because of the change of the black door, there is no doubt about it. If a single mole changes suddenly and rapidly, it is worth noting.

4. moles that grow in special parts. For example, moles growing on limbs (hands and feet) must be observed, because moles in these places are more likely to become malignant melanoma than moles in other places.

5. Mucosal nevus. Moles appeared in oral mucosa, conjunctiva, vagina and foreskin.

6. Nail groove nevus. The nail groove is connected with the skin under the nail, which may grow under the nail and be blocked by the nail, so it is not easy to see the change, and it grows at the end and is more likely to become malignant in the future.

7. Some moles are high-risk moles. The moles that babies can see at birth are called congenital moles, and there are not many congenital moles. According to statistics, 1% of newborns have moles. Not all congenital moles are inherently dangerous, and size is an important factor. Generally speaking, the bigger the mole, the greater the possibility of malignant transformation in the future, so the doctor suggested to remove it as soon as possible.

Some people have the physique of swollen crab feet, and scar tissue will proliferate abnormally, resulting in hypertrophic scars. Crab foot swelling is common in earlobe, shoulder, upper arm, chest and back, but not in face. If people with this physique want to get rid of moles for beauty, they should first inform the doctor of their physique so as not to get rid of moles for big scars.

Dangerous malignant melanoma

Ou, a plastic surgeon at MacKay Hospital in Taipei, said that benign nevus can turn into malignant melanoma: protrusion, excessive melanin, itching, pain, bleeding and ulcers.

Skin cancer mainly includes three types: malignant melanoma, basal cell carcinoma and squamous cell carcinoma.

Malignant melanoma accounts for 4% of all skin cancers, but it leads to nearly 80% of skin cancer mortality, which is one of the worst prognosis of all cancers. 10 ~ 15% patients with malignant melanoma have a family genetic history. The incidence of malignant melanoma in yellow race is lower than that in white race.

It is pointed out that 70 ~ 80% of malignant melanoma in China is acromegaly nevus, which is characterized by its predilection in palm, sole and other parts that may not be exposed to sunlight, as well as in body mucosa. Malignant melanoma of acromegaly often invades the skin basement membrane vertically and invades subcutaneous blood vessels or lymphatic vessels when the tumor is still very young, and then metastasizes. Once metastasized, the prognosis is extremely poor, and the three-year survival rate is only about 10%.

Nevus may change, some changes are warning signals, they will become malignant, and some changes are benign. Whether the nevus is malignant or not can be determined by biopsy.