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, it is much more rapid than malignant freckle-like nevus, and often develops into dermal invasive growth in 1 to 2 years when infiltration, nodules, ulceration or hemorrhage occurs, which means that the prognosis is poor. Clark (1969), after studying the relationship between the depth of invasion and prognosis of nevus, classified nevus into 5 grades according to the depth of invasion. The higher the grade, the worse the prognosis. Grade I: tumor cells are confined to the epidermis above the basement membrane. Grade II: The tumor cells break through the basement membrane and invade the papillary layer of the dermis. Grade III: Tumor cells fill the dermal papillae and invade further down, but not to the dermal reticular layer. Grade IV: The tumor cells have invaded into the dermal reticular layer. Grade V: The tumor cells have crossed the dermal reticular layer and invaded into the subcutaneous fat layer. Early examination should be performed when invasive dermal growths are detected, and their risk factors should be evaluated and scheduled follow-up and self-examination should be carried out.