Histology: In common acquired melanocytic nevi, the melanocytes are arranged symmetrically in a lateral fashion. They are arranged in nests. The nested melanocytes do not have the typical dendritic appearance of normal melanocytes found within the stratum basalis. They are round and uniform in shape and show increasing maturation with depth in the dermis. Maturation of nevi cells implies a decrease in the ratio of nuclear to cytoplasmic volume and an overall decrease in the size of the melanocytes. The melanocytes are still uniform in size and shape at various depths within the dermis; they are not symmetric vertically. Many forms are seen histologically. Based on the location of the melanocyte nests, they can be classified as junctional, intraepidermal, dermal, or compound nevi. A junctional nevus has its nests arranged along the basement membrane zone, whereas a compound nevus has epidermal and dermal nests.
Blue nevi are located entirely within the dermis. These nevi are made of melanocytes that resemble dendrites. The dendritic processes contain melanin pigment, and this pigment is responsible for the coloration of the lesion. Collagen is interwoven between the dermally located melanocytes. Melanophages are almost always seen in and around the lesion. A grenz zone is sometimes appreciated above the melanocytic lesion. Numerous histological subtypes of blue nevi have been described, including the dendritic blue nevus (common blue nevus), amelanotic blue nevus, cellular blue nevus, and epithelioid blue nevus.
Related posts:
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
