A pigmented nevus surrounded by a circle of brown color may be a normal melanocytic nevus manifestation or a malignant manifestation. Pigmented nevus, also known as nevus cell nevus or melanocytic nevus, is a benign skin tumor originating from melanocytes. Due to the different pigment content in the nevus cells, the lesions can be brown, brown, black, blue-black or skin color, and most of them do not have self-conscious symptoms. When pigmented nevus is subjected to friction, trauma or infection for a long period of time, the nevus cells will become malignant, become asymmetrical or have irregular edges, and the pigment distribution will be uneven and the color may also change. If you find that the pigmented nevus changes in color, expands or itches, it is recommended that you go to a regular hospital in time to consult a doctor who will judge the severity of the nevus and treat it according to the doctor’s instructions.