Nevus

Overview
Nevus (or naevus) is a general term that refers to a number of different (usually benign) pigmented lesions of the skin. Most birthmarks and moles are placed into the category of nevi.


 * Melanocytic nevus: Nevus cells are normally localized in the basal layer of the epidermis. Their proliferation may appear in the form of a:
 * Junctional nevus: located just superficial to the junction of the epithelium and the underlying connective tissue. A junctional nevus is flat and is not detected by palpation.
 * Compound nevus: located within the interface of the epithelium and the underlying connective tissue. A compound nevus is raised and solid.
 * Intradermal nevus: The most common lesion of the skin, these lie exclusively within the dermis. They are regular and round, their cells having a central nucleus and single nucleolus. Some melanocytes may present melanin pigment in the cytoplasm (dark-brown, granular).
 * Intramucosal nevus: Although all oral nevi are rare, intramucosal nevi are the most commonly seen there, as they are found most frequently on the hard palate.
 * Spider angioma, also known as nevus araneus
 * Dysplastic nevus
 * Blue nevus
 * Blue Rubber Bleb Nevus Syndrome
 * Nevus flammeus(port-wine stain)
 * Giant Hairy Nevus: These large pigmented (often hairy) congenital nevi are important because of their increased risk (10 to 15%) of conversion into malignant melanoma.