Moles usually include pigmented nevi (benign proliferation of melanocytes), misshapen tumors (epidermal nevi, sebaceous nevi, etc.), and others. Most of the moles on the face can be related to congenital heredity and developmental defects.
1. Pigmented nevus: pigmented nevus originates from benign proliferation of melanocytes (also known as melanocytes); congenital pigmented nevus may be related to gene mutation during embryonic development; the important reason for the formation of acquired pigmented nevus is the ultraviolet ray irradiation in the environment, and it may be related to medication, traumatic injury, hormone level change, immune suppression and so on.
Among them, dermal melanocytosis belongs to congenital, which is caused by melanocytes staying in the dermis when they move from the neural crest to the epidermis during embryonic development.
2. Miscegenation: Miscegenation refers to the wrong combination arrangement (increase or decrease of normal structure) of a normal tissue in the process of development of the body, which leads to tumor-like deformity. Skin malformation tumor refers to a large group of skin developmental abnormalities, mainly changes in epidermis, connective tissue and appendages, such as epidermal nevus and sebaceous nevus.
It is recommended that patients present with nevi that increase in size for a short period of time or affect their appearance to seek prompt medical attention and follow the doctor’s instructions.