Dermal invasive growths are one of the symptoms of superficial diffuse in situ melanoma, also known as Paget-like malignant nevus in situ. When invasive growth occurs, its speed is much faster than malignant freckle-like nevus, and often infiltrates, nodules, ulcers or bleeding appear in 1 to 2 years, that is, it develops into dermal invasive growth, and the prognosis is poor. It is most common in middle-aged people and can occur on any part of the skin, but mostly on non-exposed areas, especially on the upper back and lower legs. The damage is smaller than that of malignant freckle-like nevi, rarely exceeding 2.5 cm in diameter, and is often misdiagnosed as nevus cell nevus. It is often mildly or obviously elevated, irregular in shape, with curved or serrated edges, and some parts are curved, and characterized by variable and inconsistent hues, which can be yellowish brown, brown, light red or even blue or black, mixed with grayish white. Prevention of dermal aggressive growth should pay attention to the following aspects: 1, usually to develop good habits, pay attention to the intake of alcohol and tobacco. 2.Pay attention to sun protection, ultraviolet rays in sunlight can cause great damage to skin, and many causes of skin cancer are related to sun exposure. 3.Avoid contact with too many chemical substances. 4.Strengthen physical exercise to enhance your resistance.