Seborrheic keratosis (Dermatologic Venereology), also known as senile keratosis, is a benign skin tumor that is very common in middle age and older, and can involve both men and women without gender differences. It has a slow course and is rarely carcinogenic. There is a clear genetic predisposition. If there is a sudden increase and enlargement, it may be a sign of malignant tumor, especially gastrointestinal tumor. It can occur in any part of the body, but preferably in seborrheic areas, such as the head and face, especially the temporal area, neck, chest, back, but also in the extremities or other parts, but not in the palm top, single or multiple. In the early stage, it is light yellow-brown or tea-colored patches, with a diameter of not more than 3cm, clear boundaries and smooth surface. Later, the lesions gradually expand and elevate, and the pigmentation deepens to dark brown or black. The surface is rough and wart-like, a layer of greasy thick scab can be formed soft and brittle, after removing the scab is rough, moist base, the surface is papilloma-like, hair follicle keratosis is one of the important features. There are usually no conscious symptoms and occasional pruritus. The course of the disease is slow and the damage may expand or fuse into large masses. It can occur as a result of repeated frictional irritation with classical symptoms, rupture and bleeding, crusting and irregular hyperplasia. Treatment: 1. for benign tumors, generally no treatment is needed; 2. if necessary, topical 5-Fu ointment, cryotherapy, laser treatment; 3. for suspected malignant change, surgical treatment and pathological examination.