Pigmented nevus, also known as nevus cell nevus, is a benign tumor of melanocyte, and almost every person has more or less pigmented nevus. Because of their commonness, they are often careless and disposed of at will, teaching many lessons.
Some people listen to the nonsense of fortune-tellers, and in order to “drive away the evil and make fortune”, they randomly spot moles in the street; some people do not know the depth and take corrosive substances at will; some people randomly scratch and dig, the consequences of which are as light as leaving scars to cause deformity, and as serious as death! In order to avoid the above mistakes, it is especially important to popularize the relevant medical knowledge.
First of all, most pigmented moles are benign and do not have any effect on health. Many people worry about the malignant change of pigmented moles, which is not an empty wind. Firstly, some pigmented nevi are easily confused with some skin malignant tumors and often misdiagnosed each other; secondly, individual pigmented nevi do have certain relationship with melanoma, especially congenital pigmented nevi have a malignancy rate of about 10%, and once they are malignant, their malignancy degree is extremely high and their metastasis rate is also the fastest, and the treatment effect is not ideal, so we should pay necessary attention to black pigmented nevi and ask dermatologists to identify them when necessary.
Secondly, it is also important to distinguish the types and distribution of pigmented nevi. From the perspective of tissue morphology, pigmented nevi can be divided into junctional nevi, mixed nevi and intradermal nevi. Junctional nevus is usually flat on the surface of the skin, and the nest of nevus cells is limited to the epidermis; mixed nevus can be slightly elevated on the surface of the skin, and its nest of nevus cells involves both the epidermis and the dermis; intradermal nevus is a bulging spherical swelling, sometimes with hair growth, and its nest of nevus cells is all in the dermis.
Some junctional nevi may transform into mixed nevi and intradermal nevi with body development, that is to say, pigmented nevi can change from small spots to large and elevated. From the time of occurrence, pigmented nevus can be further divided into congenital pigmented nevus and acquired pigmented nevus. Congenital pigmented nevi occur at birth or shortly after birth and generally become larger as the body develops. Some congenital pigmented nevi are very large and have hair growth on the surface, called hairy epidermal nevi, and larger ones are called animal skin nevi.
Acquired pigmented nevi are pigmented nevi that occur in adults and are flat on the surface of the skin at the beginning, but some of them gradually elevate and even grow into intradermal nevi with hair growth.
Intradermal nevus
Mixed nevus
Crossborder nevus
Congenital pigmented nevus
Pigmented nevus malignant transformation
Again, the most important thing is to be alert to “nevus transformation”!
1.The lesion grows faster or the size of the lesion does not change significantly, but it thickens significantly.
2. Color change, darkening, or especially the appearance of light blue tones.
3, occurrence of hair loss, decrusting or the appearance of satellite foci.
4.The surface is broken, bleeding, and ulcers are formed.
5.Unexplained symptoms such as itching or pain, inflammation, etc. appear.
For the sake of memory, the malignant tendency of nevus is described as “ABCDEF” phenomenon. That is, asymmetry, border irregularity, color change, diameter greater than 6mm, evolution (clinical change) and risk factor (risk Factor) (blond hair, fair skin, dysplastic nevus syndrome, high number of nevi, etc.).
Generally speaking, junctional nevi, congenital pigmented nevi especially giant nevi have a tendency of partial malignant transformation! Most of the acquired pigmented nevi are benign, but special attention should be paid to the pigmented nevi that grow out suddenly and change obviously, as well as the pigmented nevi on the friction parts such as hands and feet and the contact parts of upper and lower lips.
Principles of treatment of pigmented nevi.
Since pigmented nevi are closely related to malignant melanoma, the treatment of pigmented nevi mainly involves two major issues, one is to ensure safety and the other is to ensure the cosmetic effect, whether for cosmetic needs or for the purpose of preventing malignant changes.
No matter what kind of laser is used, the mole cells cannot be completely removed. The residual mole cells may recur and become malignant. Another very dangerous aspect is that the tissues that cannot be removed by this method are subjected to timely pathological examination, which can easily lead to misdiagnosis and missed diagnosis. Especially, early malignant melanoma cannot be disposed of in time.
Therefore, we call for
1. No matter what the purpose is, the principle of treatment for nevus is “if it is not treated, it should be treated completely”.
2. To remove congenital nevi as much as possible prophylactically.
3. Laser, freezing and drug erosion are prohibited to treat nevus with dangerous tendency.
4. Routine pathological biopsy of excised specimens should be performed, and if malignant changes are found, the excision should be expanded and treated as appropriate.