Melanocytic nevushttps://en.wikipedia.org/wiki/Nevus
Melanocytic nevus is a type of melanocytic tumor that contains nevus cells. The majority of nevi appear during the first two decades of a person's life. With about one in every 100 babies being born with nevi. Acquired nevi are a form of benign neoplasm, while congenital nevi are considered a minor malformation or hamartoma and may be at a higher risk for melanoma. Benign nevus are circular or oval and are usually small (commonly between 1–3 mm), though some can be larger than the size of a typical pencil eraser (5 mm). Some nevi have hair.

Treatment
Laser surgery are commonly done to cosmetically remove small nevi. If the size is larger than 4-5 mm, surgical excision may be required. In young children, a nevus larger than 2 mm in size is often difficult to be completely removed without scarring.
#CO2 laser
#Er-YAG laser
  • Normal nevus
  • Becker nevus ― Shoulder; characterized by the growth of hair on the nevus.
  • Nevus of Ota ― Appears blue due to the deep location of nevus cells in the dermal layer. In this patient's case, the nevus is located on the conjunctiva. Ota nevus can be removed through laser treatment.
  • Compound nevus ― Buttock. Small birthmarks can grow to large nevi with age.
  • Intradermal nevus ― The shape of a protruding nodule.
  • Normal nevus. The two photographs below are intradermal nevus, and the three photographs above are junctional nevus.
  • Blue nevus ― Due to the deep location of nevus cells, it appears blue.
  • Intradermal nevus ― It is commonly observed on the scalp.
  • This picture indicates a nevus lesion. However, if the main lesion is small like this, the algorithm may not be able to accurately predict the condition.