Moles are no stranger to any of us, and many people have moles of varying sizes, more or less, on their bodies. According to statistics, upon careful circumferential examination, normal individuals can have as many as 50 moles, and generally have as many as 15 to 20 moles on average. What exactly happens when you have a black mole on your body? Moles are not all tumors. The vast majority of moles are benign and do not have any effect on health. 1. It is true that some moles are easily confused with some skin malignant tumors and misdiagnosed each other; 2. It is true that individual black pigmented moles are somewhat related to melanoma, so the necessary attention should be paid to black pigmented moles. Most nevi are benign Black nevi, also known as pigmented nevi, colored nevi or spotted nevi, are composed of normal nevus cells containing pigment, and are most commonly benign tumors of the skin. Most of them are dark brown or black in color, but there are also colorless moles without color. There are three main types of nevi: junctional nevi, which are light brown, brown-black or blue-black in color and have the potential to become cancerous and can occur as melanoma. Intradermal nevus, which is darker and more uniform, light brown, dark brown or black, usually does not develop cancer. Mixed nevus is a mixture of the above two kinds of nevi, generally like intradermal nevus, which may also become cancerous because of the junctional nevus component. Nevi can be seen on any part of the body, but they are most common on the face, neck, back and other parts. Some of them are innate and exist at birth; others are the products of the later life and appear one after another after two years of age. Most of the moles grow slowly or continue for many years without changes or symptoms. With age, nevus cells gradually move from the superficial layer of the skin into the dermis, and their number gradually increases, usually peaking at puberty. “The vast majority of pigmented moles are benign and stay with each other for life, safe and sound.” Dermatologists say. Special types of moles to be careful Although most pigmented moles are benign, there are still a few special parts and special types of moles that have the tendency to become malignant, and the public should pay attention to them. Moles that grow on the palms of hands, feet and genital areas (mostly junctional moles) are prone to lesions due to frequent friction. In particular, moles on the soles of the feet, which are not itchy and painless, are actually the most dangerous “terrorists”. Secondly, moles on the head, neck and face are also susceptible to lesions due to long-term sun exposure, especially black pigmented moles on the face of the elderly. Generally, new moles are less likely to occur after the age of 30. If a new mole occurs and its diameter exceeds 0.5 cm, you should go to a regular hospital dermatology department for diagnosis in time to exclude malignant melanoma. There is another kind of nevus, mostly seen in middle-aged and young people, mostly on the trunk, which is a pigmented spot the size of a bean, with uneven color and unclear edges, called dysplastic pigmented nevus. If it presents multiple nevi, it should be highly noted that there is a potential risk of developing into malignant melanoma. In addition, congenital giant pigmented nevus should also be noted. This kind of pigmented nevus is present at birth, with huge lesions, often involving the whole scalp, most of the trunk and half of the limbs. They are dark, brownish-black or black in color, with dark, thick and dense hair on the surface, sometimes accompanied by other developmental abnormalities, and in a few cases, they may become malignant. Moles easily confused with nevi In terms of clinical differentiation, moles that are easily confused with nevi are mainly concentrated as follows: giant nevus. Giant nevi are generally considered to be located on the trunk and limbs, with an area of more than 900 cO. However, the criteria for giant nevi should vary according to age and location. For example, pigmented nevus in specific areas such as face, although the area is less than the above criteria, but the trauma cannot be directly sutured after surgical excision, it can also be considered as giant nevus. Infants and children cannot be measured by this standard. Giant nevi are present at birth and are often multi-locally invasive, often with an uneven, rough and hypertrophic surface, and often with hair. The pathological nature of macromegaly is mixed or intradermal, so there is also the possibility of transformation into malignant melanoma. Freckles. It is a diffuse and scattered distribution of numerous small light brown spots, with smooth surface and not protruding from the skin. They are usually found on the exposed sun-exposed parts of the body, most notably on the face, and occasionally on the neck, shoulder, back of the hand, etc. On examination of tissue sections, the number of melanocytes does not increase, but a large number of pigment granules are formed abnormally. Age-related dark spots. They occur in the exposed parts of the body of middle-aged and elderly people, such as cheeks, neck, back of hands and forearms, etc. They are mostly scattered in brownish color, with small round, oval or irregular-shaped smooth or slightly higher than the skin surface patches. Histological examination shows an increase in normal melanocytes without malignant transformation. The treatment of moles varies from person to person. For larger facial nevi without signs of malignancy, partial excision by stages can be considered for better preservation of appearance and function, but it is not applicable to those with malignant tendency, or total excision, or adjacent flap transfer or free skin grafting can be used. If the patient suspects malignancy, the surgeon can use shell surgery to remove all biopsies at once, and the surgery should be performed with an incision in the normal skin, beyond the border of the mole. Moles that must be small are excised and then can be pulled together and sutured directly after subtle peeling of the skin’s traumatic margin.